cb(1)1537/12-13(07) - legco hypocrisy to jet across hansen and bloomberg ... cb(1)1537/12-13(07) 1...
TRANSCRIPT
Submission to the Panel on Env Affairs – upgrading of Diesel Standard for vessels. Submission from CO2 Feeds the World – Dr Robert Hanson This submission should be read in conjunction with the AQ reported submitted by Carbon Consultants.
1. All engines should be upgraded to a HK 6 standard in the shortest possible time. 2. No vessel engine should be operating at below EU 4 by the end of 2014 3. This should apply to all engines used in vessels, NMM, and all transport as a
fully integrated policy. 4. All new engines for every vessel and vehicle should meet EU/HK 6 with
immediate effect. 5. HK should develop its own stds for engines - higher than other countries –
necessary given the density and geographical layout of HK – which naturally traps pollutants.
6. The government should resist all carbon trading schemes and carbon footprint audits and focus on DIRECTLY on reducing criteria air pollutants (PM, NOx in particular) - carbon trading schemes benefit bankers and traders who in turn use their huge bonuses from these schemes to lead highly polluting lifestyles. CO2 is not a pollutant – so leave it alone – it is a distraction – many companies and individuals can be carbon neutral but at the same time be highly polluting. All effort, all focus should be on reducing criteria air pollutants.
7. All government members, EXCO members and LEGCO members should lead by example – and on a web site provide details of the pollutants they have produced each month – for public scrutiny.
8. All conferences aimed at reducing pollution should not involve air travel – it is pure hypocrisy to jet across Hansen and Bloomberg (by private jet) from the US to take about global warming – such a conference was a disgrace. As is HK government members flying to C50 and other conferences; this must stop.
9. All major companies and Consulates, such as CLP, HSBC, Cathay Pacific, and the British Consul (many pay lip service to being green) should also add on the gov website the pollutants produced by all their directors both during the course of business and in their personal lives (it is the income from their work used to pollute in their personal lives). They should list miles flown – and what class and type of transport used in HK and pollution produced. We do mean all pollutants that form part of the AQ index and not C02 – people and companies can be CO2 neutral but highly polluting – it is important to focus purely on reducing all pollutants forming part of the AQ index and not be distracted by CO2.
10. All members of government, and directors of quoted companies on THE stock exchange that claim to be green as a way of promoting themselves or their companies should be forced to use public transport and not fly or use air conditioning units – these create pollutants harmful to AQ.
Upgrading vessels is supported – but it should be part of an integrated policy incorporating the above. Dr Robert Hanson CO2 FEEDS THE WORLD
CB(1)1537/12-13(07)
1
Improving Air Quality in Hong Kong
A Report to the Government of the Hong Kong Special
Administrative Region
by
Carbon Consultants
for Carbon Consultants,
20th September 2012
................................................................ ...........................................................
Dr Robert Hanson John Robertson BA (Hons), MA, LL.M, Barrister, PGCE, MA Engineering (Cantab), OBE PhD Built Environment
2
Table of Contents Executive Action Summary Page 4
Clean from the Bottom up; HK1 to HK6 - time line to 31/12/2018 Page 5
Questions and Answers on Hong Kong’s Air Quality Pages 6 – 12
Short Report Pages 13 - 17
Hong Kong Vehicles by Emission Standards 2011 Page 13 - 14
Fuel Use in Hong Kong Page 14
Sulfur in Fuel Page 15
NOx in Exhausts – a critical pollutant for Hong Kong Page 15
Ozone at Ground Level Page 16
Carbon Monoxide – a Killer Page 16
Volatile Organic Compounds VOCs and SMOG Page 16
World Health Organisation (WHO) Air Quality Guidelines Page 16 - 17
The 6-Rs of Diesel Clean Up Page 17
Power of Hong Kong’ Example to the World Page 17
Cost/Benefit Analysis Page 17
Improving Air Quality in Hong Kong – More Detailed Report Pages 18 - 42
References in the Report Page 18
Air Quality problems today in Hong Kong Pages 18 – 21
Wind borne pollution from neighbours Page 21
Vehicle pollution from neighbours Page 21
Fuel Use in Hong Kong Page 22
EPDHK Air quality trends in Hong Kong 1999-2010 Page 22
Large use of diesel fuel in HKSAR – need for very high standards Pages 22 - 23
World Health Organisation Air Quality Guidelines Page 23 - 24
Ground level Ozone (O3) and PANs – the hidden enemy Page 24 - 25
Country comparisons of air pollution with Hong Kong Page 25 - 27
SO2 – a success story – Castle Peak Power Station retro-fit Page 27 - 29
PSP (PM) and NOx from engines – a sad story Page 29
Catalytic converters in petrol and LPG vehicles Page 30
Hybrid rather than LPG taxis? Page 30
Diesel engine clean up Page 31
Government sets standards – users choose how to meet them Page 32
Diesel Particulate Filter DPF Page 32
Selective Catalytic Reduction SCR – a Critical Technology Page 33
Ultra-low sulfur fuel for ALL diesel engines Page 33
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Diesel Oxidation Catalyst DOC – a comparison Page 33
DPF and SCR are not prescriptive Page 33
Installation, Maintenance and Testing IMT – essential Page 34
What standards should be set – Hong Kong’s own; HK1 to HK 6 Pages 34 – 35
China’s EURO VI compliant diesel engine 2011 Page 35
Hong Kong’s streets are very clean. Its air should be equally clean. Page 36
Set strict emission standards and fine breaches heavily Page 36
Pollution Reduction; Owner pays; Government alleviates hardship Page 37
Costs to Users and Operators Page 37
Costs to Government Page 37
Pareto Principle – get rid of the bad engines urgently Page 37
CCS for power stations – failures - avoid like the plague Pages 38 – 40
The Port of Hong Kong, World Shipping and the IMO Pages 40
Phase out 2-stroke motors Pages 40 - 41
Conclusion – Implement HK6 by 31st December 2018 Page 52
Appendix - Relationship between Emission of CO2
by a Diesel Engine and Emission of Criteria Pollutants Pages 53 – 57
This report identifies the real air quality problem in Hong Kong, shows why
it has not been solved by the well-intentioned measures taken to date and
lays out a strategy to give Hong Kong clean air within a structured 6-year
time span.
4
Prologue
Bad air quality in Hong Kong is all too familiar. The harm it does to the amenity, well-being
and health of all has been described and reported countless times. The damage it does to
Hong Hong’s economy, “the most polluted air of any world financial center” (Bloomberg News)
is also a painful fact. Public perception and official reports indicate that matters are getting
worse rather than better. A recent leading article in the South China Morning Post reported
that air quality in Hong Kong in 2012 is the worst that has ever been measured.
So what to do? Answer: capture the two villains responsible: PM (RSP) and NOx. Much
more about them follows later.
These villains are home grown and lurk in the exhausts of every internal-combustion engine
in Hong Kong. Their favourite hideout is in old diesels.
This report is about how to capture them and convert them into good citizens. When
captured and reformed, PM becomes benign carbon dioxide (CO2) - the vital basis of all
plant growth. NOx becomes nitrogen (N2) – the main constituent of clean air - plus pure
water (H2O).
Lasting credit will accrue to those who make the capture and bring about the reformation.
All who live and work in Hong Kong will experience massive and continuing benefit as a
result.
What action is needed to make this happen? Legislate for high emission standards for all
vehicles, construction plant, vessels and other engines in Hong Kong by means of HK1 to
HK6. (Details and timeline are on page 6). Monitor and enforce those standards rigorously.
PM alias
RSP
Reward: HK$100 billion
NOx
Reward: HK$100 billion
5
Executive Action Summary
1. Recognise that bad air quality in Hong Kong damages the health of
its citizens, reduces their amenity, harms the environment, wounds the
economy and is unworthy of ‘The Fragrant City’.
2. Resolve to clean up the old and dirty engines which are the main cause
of bad air quality Hong Kong. Simultaneously require all new engines
to meet the highest international emission standards. Doing this is
essential to give Hong Kong clean air. Consistently clean air will benefit all citizens’ well-being, improve the environment, strengthen the economy and bring lasting credit to those who make it happen.
3. Create new HK1 to HK6 emission standards related to the EURO
equivalent but applying to existing vehicles and engines as well as to
new ones. Existing engines will require to be upgraded or, if upgrading
is not possible, to be scrapped progressively from 2013 onwards until
all are of HK6 standard by 31/12/2018. See time-line on page 6.
4. Apply the HK standards to all internal combustion engines on
the land or the waters of HKSAR be they in cars, trucks, buses,
construction plant, port or airport equipment, ferries or other local
vessels.
5. Require owners of vehicles or engines to choose how they
meet the standards and then to pay the costs thereof.
6. Accept that this will cause real hardship for some and establish a fund
to alleviate it. In this context ‘real hardship’ means a threat to
employment or livelihood – not mere cost or inconvenience.
7. Extend the existing requirement that all road vehicles in Hong Kong
use ultra-low-sulfur (<10 ppm sulfur) diesel to all diesel engines used
in HKSAR including those in ferries.
8. Filter out diesel smoke in diesel exhausts; not in human lungs. Get rid
of the NOx and the SMOG will get rid of itself.
6
Clean from the Bottom Up
Europe has led the way in successfully cleaning up what was notoriously dirty air in some of
its big cities. A key element has been control of exhaust emissions from vehicles and other
engines. Please see tables on pages 17-21.
In most countries emission standards apply to new vehicles coming on to the road but not to
existing ones. Because of the very large fuel use per Km2 of land area in HKSAR compared
to world average, this process will not suffice for Hong Kong. High standards for new
vehicles will, of course, be essential but they alone will not be sufficient to clean Hong
Kong’s air within a reasonable period. Old and polluting engines on the roads, construction
sites or waters of Hong Kong will need to be upgraded or removed from service to meet the
higher standards. This will be a very big task and will require total concentration to achieve
it. The prize is great.
The HK technical standards will lie securely within the envelope of international EURO
standards (set out in detail on page?) to ensure that vehicles are available from the
international market to meet Hong Kong’s needs. For diesel engines which are not on the
roads but on construction sites or ferries for example, the EURO standard for heavy duty
diesels based on allowable emissions per KWhr will apply from HK1 to HK6. HK6 will
apply the European requirement relating to particle emission per kilometre to vehicles but
not to off-road diesels or to those in ferries and other vessels.
HK1 to HK6 will also apply to all existing engines. After 2018 HK6 will apply one uniform,
high standard to new and old right across the board. Until that time the HK standards, on a
scale which rises annually, will derive from the ‘EURO’ standards and will be as follows
over the years 2013 to 2018:
Year Existing Engines by year end New Engines all year
HK1 2013 EURO I or higher EURO V or higher
HK2 2014 EURO II or higher EURO V or higher
HK3 2015 EURO III or higher EURO V or higher
HK4 2016 EURO IV or higher EURO VI (HK6)
HK5 2017 EURO V or higher EURO VI (HK6)
HK6 2018 EURO VI (HK6) EURO VI (HK6)
Existing engines which do not comply must be upgraded to the required level or withdrawn
from use. By the end of 2016 only EURO IV or better (HK4) will remain in Hong Kong. The
upgrade or removal of dirty engines cannot be optional.
7
Improving Air Quality in Hong Kong
Statistical Tables, Standards and Other Key Data on which this Report is
Based
Distribution of Vehicles in HKSAR according to Emission Category for Year 2011 -
Courtesy of EPDHK – the Environmental Agency of the Hong Kong Government
EPDHK maintains excellent statistics on the factors affecting the air quality of Hong Kong.
They have kindly made the following tables available to the authors who have added totals
in bold.
Emission Categories
Vehicle Class
Pre-
Euro Euro I Euro II
Euro
III
Euro IV
or
above
Pure
Electric
Vehicles
No of Licensed Vehicles
Private Cars (Petrol) Totals
<1500 cc 3,798 16,560 16,506 26,306 37,108 172 100,450
1501-2500cc 5,828 20,304 23,050 61,028 99,326 209,536
2501-3500cc 2,032 6,473 8,866 30,589 45,110 93,070
3501-4500cc 806 1,211 638 5,170 6,783 14,608
>4500cc 938 709 1,403 3,219 8,867 15,136
Private Cars (Diesel)
<1500 cc 1 0 0 0 0 1
1501-2500cc 568 231 19 1 0 819
2501-3500cc 404 407 46 2 328 1,187
3501-4500cc 13 1 0 0 0 14
>4500cc 0 0 0 0 0 0
Goods Vehicles
< =1.7 tonnes 13 0 1 3 0 6
23
> 1.7 tonnes 17,802 12,061 21,894 27,449 31,935 111,141
Public Buses 449 1,056 4,143 3,636 3,500 0 12,784
Private Buses 47 22 108 151 164 1 493
Public Light Buses 21 328 492 2,860 644 0
4,345
Private Light Buses 343 378 286 343 844 4 2,198
Taxis 1 1 14,402 1,517 2,322 0 18,243
Motorcycles 5,211 18,510 0 14,830 0 15
38,566
Totals 38,275 78,252 91,854 177,104 236,931 198 622,614
% of Totals 6.1% 12.6% 14.8% 28.4% 38.1% 0.03% 100%
Remove or upgrade by end of: 2013 2014 2015 2016 2017
All vehicles will be HK6 by end of 2018. Hybrid vehicles in the above table are classified as petrol.
8
Non-Road Mobile Machinery (NRMM) – data courtesy of EPDHK
Number & applications: There are about 13,500 units of NRMMs operating in Hong Kong.
11,300 units are operating at construction sites, 1,600 units at the airport and 600 units at
container terminals.
Age and service life: The estimated average age and the average service life remaining of
these NRMMs are about 8 years and 14 years respectively.
Type of fuel used: Mostly diesel driven.
Engine size: In great diversity, small engines of several kW to large engines of more than
several hundred kW.
Emission contributions: About 7% (6,800 tonnes) and 11% (600 tonnes) of the local
emissions of nitrogen oxides and respirable suspended particulates respectively. (Authors’
note: these emissions come from some 2% of the total engines in use in Hong Kong.)
Urban Construction; a Hong Kong Street Scene
Photo: Robert Hanson, July 2012
See also: http://www.healtheffects.org/Slides/AnnConf2012/Wall-SunPM.pdf
9
Distribution of Installed Engines on Ferries for Year 2011 (at June 2011)
Number of Licensed Ferries: 56
Engine Type Number of Engines
Installed
Average Engine Age
(years)
Average Engine Power
(kW)
Main Engine 98 20.6 859.9
Auxiliary
Engine 121 24.2 100.3
All engines are diesels. Engine age was calculated by the built year of the vessels.
Hong Kong Ferry Berth - Photo: Robert Hanson Sept 2012
What does this mean for Hong Kong’s Air Pollution?
The calculations which follow are based on the EPDHK tables above and on the EEC EURO
emission tables (on pages 17-21). They total the current levels of NOx and PM pollution in
tons per day from vehicles and other engines in Hong Kong and compare that with what the
same numbers of vehicles and engines would produce if they were to HK6 (EURO VI)
emission standard. The improvement is dramatic!
They make the detail assumption that pre-EURO emission levels are, on average, 1.5 times
the EURO I figures for PM and 1.25 times for NOx. They also make assumptions (shown in
italics) about engine power and the annual hours or kms of use. If those assumptions are in
error, the results on both sides of the ledger will change correspondingly. The comparison
and the conclusion will not change.
10
Diesel Trucks & Buses
A truck or bus is assumed to average 80 Kw and to run for 1,000 hours per year.
PreEURO EURO I EURO II EURO III EURO IV
EUROVI/HK6
17,802 12,061 21,894 27,449 31,935 Trucks
449 1,056 4,143 3,636 3,500 Public Buses
47 22 108 151 164
Private Buses
Totals 18,298 13,139 26,145 31,236 35,599 Total
Diesels 124,417 NOx 10 8 7 3.5 2 Euro Limits 0.4 grams/Kwhr
PM 0.9 0.61 0.15 0.1 0.02 Euro limits 0.01 grams/Kwhr
Pollution Emitted in Tons/Day
Current Totals HK6 totals
NOx 40 23 40 24 16 143 11 Tons/Day
PM 3.6 1.8 0.9 0.7 0.2 7 0.3 Tons/Day
Non-Road Mobile Machinery (NRMM) – data courtesy of EPDHK
EUROVI/HK6
Average machine is assumed to be 80 Kw and to operate for 3,000 hours/yr 13,500 Emissions at present as per EPDHK estimate.
Euro Limits 0.4 grams/Kwhr
Euro limits 0.01 grams/Kwhr
13,500
Current Totals HK6 totals
NOx 18.6 Per EPDHK
18.6 3.6 Tons/Day
PM 1.6 Per EPDHK
1.6 0.1 Tons/Day
Ferries - data courtesy of EPDHK
Engines as per EPDHK. They are over 20 years old so are assumed to be pre-EURO.
They are assumed to operate for 3,000 hours per year.
83,888 98 @ 856 Kw each
12,100 121 @ 100 Kw each
EUROVI/HK6
95,988 Kw total
95,988
NOx 10
Euro Limits 0.4 grams/Kwhr
PM 0.9
Euro limits 0.01 grams/Kwhr
Pollution Emitted in Tons/Day
Current Totals HK6 totals
NOx 7.9
7.9 0.3 Tons/Day
PM 0.7
0.7 0.01 Tons/Day
11
Private Cars, Taxis, Light Buses, Commercials and Motorbikes
Average petrol/LPG vehicle is assumed to travel 10,000 km per year
PreEURO EURO I EURO II
EURO III
EURO IV
EUROVI/HK6
Totals 19,977 65,113 65,709 145,868 201,332
497,999
NOx 0.25 0.2 0.2 0.15 0.08 Euro Limits 0.06 grams/Km
PM 0.9 0.61 0.15 0.1 0.02 Euro limits 0.005 grams/Km
Pollution Emitted in Tons/Day
Current Totals HK6 totals
NOx 0.1 0.4 0.4 0.6 0.4 1.9 0.8 Tons/Day
PM 0.5 1.1 0.3 0.4 0.1 2.4 0.1 Tons/Day
Summary of Change:- Current HK6
NOx 179 15.9
PM 12 0.4
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They underline once again that older diesels are the problem and that their upgrading or
removal is the key to good air quality in Hong Kong.
‘Criteria air pollutants’
'Criteria air pollutants' is a term used internationally to describe air pollutants that are
regulated and used as principal indicators of air quality. The regulations or standards are
based on criteria that relate to health and/or environmental effects. The six pollutants are:
Carbon Monoxide (CO)
Lead (Pb)
Nitrogen Dioxide (NO2)
Ozone (O3) Particles, i.e. smoke or very fine dust, (PM10, PM2.5) - Called RSPs by EPDHK
Sulfur Dioxide (SO2)
Carbon monoxide (CO) is the product of incomplete combustion of any solid or liquid fuel.
In a piston engine the fuel-air mixture has a very short time to burn (0.01 seconds at 3,000
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rpm) and so combustion is often not complete when the exhaust valve opens. This is
exacerbated if the mixture is ‘rich’, e.g., when starting. A petrol engine typically has around
0.7% of CO in the exhaust as it leaves the cylinders. CO is fatal at about 0.08% in the
atmosphere.
Piping the exhaust into a closed car was quite a common resort of intending suicides before
the advent of modern catalytic converters. Today these catcons oxidise about 95% of the CO
to benign CO2. This brings CO below the fatal level when leaving the exhaust. In the open
air it dilutes rapidly to become innocuous.
CO is dangerous if indoor combustion heaters, however fuelled, are inadequately ventilated.
Beware also that small petrol engines on, say, lawn mowers or household generators, do not
usually have catcons so the CO in their exhaust fumes can be fatal in closed spaces.
‘Town-gas’ is still used by about 1.7 million Hong Kong residents. This gas has 1% to 3% of
CO. This concentration is well into the fatal range so ‘putting your head in the gas oven’ is
still a lethal possibility for those users. The gas has a special odour added to prevent
accidental poisoning.
Lead (Pb) was very important thirty and more years ago because it was used widely to
improve the octane rating of petrol. Now in most parts of the world it is no longer a
significant pollutant as lead in petrol has been banned. There is no lead in diesel fuel and
there never was. Lead remains important as dust in the vicinity of Lead-Zinc mines and as a
constituent of old paint.
Nitrogen Oxides (NOx)
Nitrogen Oxides, (NOx) are of especial importance in Hong Kong. There are many such
oxides, viz:
Nitric Oxide NO Nitrogen Dioxide NO2 Nitrous Oxide N2O Dinitrogen Trioxide N2O3 Dinitrogen Tetroxide N2O4 Dinitrogen Tetroxide
N2O5
Nitrogen oxides are produced during high temperature combustion of solid, liquid or
gaseous fuel in air. The air itself is about 78% nitrogen so there is ample present but nitrogen
(N2) is generally very reluctant to combine with the 21% of oxygen (O2). It takes
temperatures over 1,500oC to make it happen.
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In addition there are a variety of substances that are not polluting in their own right but
which can react with one or more of the nitrogen oxides to give unpleasant or dangerous
products. Some of those are components of SMOG. This term was coined long ago to
describe the “Smoky Fog” then common in big cities such as London. In those days smog
was the product of coal fires. The smoke and SO2 coming from burning coal in open
domestic fires gave choking SMOG. The UK Clean Air Acts of the 1950s cleared that type of
smog by banning open coal fires in towns and cities.
Today NO2 quite often fills the disagreeable role that SO2 did in decades past and itself
forms reddish-brown smog. Today’s smog is also photochemical. That is to say it is caused
by reactions between the NOx and a wide variety of volatile organic compounds (VOCs)
under the action of strong sunlight. The smog consists of one or more of NO2, O3 and PANs.
Ozone O3
O3 has a split personality. When it is high in the stratosphere it provides an essential
protective blanket shielding us and other animals from excess ultra-violet rays. All countries,
including Hong Kong, agreed to ban the use of fluoro-carbon refrigerants because they were
destroying the ‘ozone layer’ and potentially exposing us to skin cancer and other harmful
effects. This was a very good example of everyone acting in unison to stop damaging
pollution. Sound science brought immediate general consent and action notwithstanding the
cost.
However, at ground level ozone is a different beast altogether. It is produced by the
interaction of NOx (NO2 especially) and VOCs (see below) in strong sunlight. It is a major
cause of photochemical SMOG.
Respirable Suspended Particulates RSP, PM10, PM2.5 They have many technical names but are usually called PM – Particulate Matter. PM is a
complex mixture of extremely small particles and liquid droplets. Particle pollution is made
up of a number of components, including acids (such as nitrates and sulfates), organic
chemicals, metals, and soil or dust particles.
The size of particles is directly linked to their potential for causing health problems. Small particles less than10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream.
Exposure to such particles can affect both your lungs and your heart. Small particles of concern include "inhalable coarse particles" (such as those found near roadways and dusty industries), which are larger than 2.5 micrometers and smaller than 10 micrometers in
14
diameter; and "fine particles" (such as those found in smoke and haze), which are 2.5 micrometers in diameter and smaller.
Particle pollution - especially fine particles - contains microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:
premature death in people with heart or lung disease, nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, and respiratory symptoms, such as irritation of the airways, coughing or difficulty
breathing.
People with heart or lung diseases, children and older adults are the most likely to be affected by particle pollution exposure. However, even if you are healthy, you may experience temporary symptoms from exposure to elevated levels of particle pollution.
PM has other bad effects including:
Impaired visibility. Fine particles (PM2.5) are one of the main causes of reduced visibility in Hong Kong.
Aesthetic damage. Particle pollution can stain and damage building stone and other materials, including culturally important objects such as statues and monuments.
Sulfur Dioxide SO2 SO2 is important whenever a fuel containing sulfur (S) is burned. Some coals have 4% sulfur or even more. The coal used in Hong Kong power stations is at the opposite end of that scale with very low sulfur. Allied to Wet Flue Gas Scrubbing, this has led to the level of SO2 in Hong Kong’s air being well below the WHO guidelines. It is the only criteria pollutant (other than lead) in that happy state in Hong Kong and that reflects particular credit on the electricity utility companies. Electricity generation from coal is typically the main cause of SO2 pollution worldwide. The low levels in Hong Kong are admirable. For solid fuel, i.e. coal, it is only practicable to absorb and remove the sulfur after combustion. For liquid fuels such as diesel it is much better to remove the sulfur at the oil refinery. The recovered sulfur has a significant value. The ultra-low sulfur fuel now mandated for road vehicles (<10 ppm S) in Hong Kong means that SO2 from vehicles is negligible. The ultra-low sulfur in diesel is very important to optimize the performance of DPF and SCR pollution controls (see further below) on diesel engines. Sulfur in Fuel All fossil fuels contain some sulfur. For modern oil fuel, sulfur is removed at
the oil refinery so that its level is negligible (0.001%). When sulfur is burned it produces
highly toxic and damaging sulfur dioxide (SO2) which is a critical air pollutant. The burning
15
may also produce smoke. In the jargon of air quality this smoke is called Particulate Matter
(PM) or Respirable Suspended Particles (RSP). Such tiny particles, especially those from
diesel engines, are very harmful to health.
Around the World coal-burning power stations are, by far, the main source of sulfur
emissions. It is much to the credit of the power utilities in Hong Kong, therefore, that the
current SO2 levels as measured by EPDHK are about half of the WHO guidelines. This is
despite the use of about 11 million metric tons of coal annually to produce Hong Kong’s
electricity. It is highly commendable and shows the way to go:
Top Technology + Capital = Clean Air
And Two Extras:
VOCs range from petrol spilt and evaporated on a service station forecourt, through
unburnt fuel emitted from a car’s exhaust to natural oily vapours from trees. For example, in
the City of Brisbane in Australia some 60% of the VOCs come from the splendid Eucalyptus
trees growing profusely throughout the metropolis. Methane, natural gas, (CH4) is usually
excluded from VOCs and they are sometimes called NMOGs – Non-Methane Organic Gases.
The reactions and the balance between NO, NO2 and O2 is complex. In strong sunlight they
react with the VOCs to produce SMOG – mainly as NO2, O3 or PANs.
However, if NOx is not present this does not happen.
PANs, Peroxyacyl Nitrates (also known as APNs), are powerful respiratory and eye irritants. They are produced by the gas-phase oxidation of a variety of volatile organic compounds (VOCs), or by aldehydes and other oxygenated VOCs oxidizing in the presence of NO2. The final step is a combination of a peroxyacyl radical and NO2 for example, peroxyacetyl nitrate CH3C (O)OONO2.
CH3C (O)OO· + NO2 → CH3C(O)OONO2
PANs are toxic and irritating because they dissolve more readily in water than Ozone O3. They are lachrymators, causing eye irritation in concentrations of only a few parts per billion. At higher concentrations they cause extensive damage to vegetation and human tissue. Both PANs and their chlorinated derivatives are said to be mutagenic; that is, they can cause cancer – especially skin cancer.
A PAN molecule schematic
Again, if NOx is not present PANs do not form.
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Air quality trends in Hong Kong 1999-2010 Source: EPDHK μg/m
3 is micrograms per cubic metre.
On the excellent graphs above it is important to note that in 2010 the NOx (and NO2) are
much higher at the roadside than they are generally. The same goes for RSP (PM). This
shows that those pollutants are mainly being generated on the road and spill out from
there into the air of Hong Kong City. Both are at levels far too high to permit clean air. By
the same token reducing them is the key to achieving clean air.
Air Pollution Worldwide
What does the World Health Organisation (WHO) have to say about air pollution? The information is contained in a 2005 update report, titled as below:
WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide
and sulfur dioxide Global update 2005 - Summary of risk assessment
The WHO estimates that some 1.3 million people per year die from the effects of outdoor air
pollution. Many more suffer ill health due to it. In its 2005 update WHO identifies the four
main pollutants listed above to be the crucial determinants of air quality. It goes on to set
guidelines recognising that the circumstances of each individual country may lead that
17
country to mandate different numbers. The guidelines set different standards for short term
(say, 24 hours) exposure and the long-term average over an entire year.
The WHO statement of the purpose of the Air Quality Guidelines reads as follows:
“The following sections of this document present the WHO AQGs for PM, Ozone, NO2 and SO2, and in each case give the rationale for the decision to revise the guideline value or to retain the existing value. As noted above, the epidemiological evidence indicates that the possibility of adverse health effects remains even if the guideline value is achieved, and for this reason some countries might decide to adopt lower concentration than the WHO guideline values as their national air quality standards.”
The current WHO air quality guidelines are as below.
Particulate Matter PM2.5: 10 μg/m3 annual mean PM10: 20 μg/m3 annual mean 25 μg/m3 24-hour mean 50 μg/m3 24-hour mean
(<2.5 microns diameter) (<10 microns diameter)
Ozone O3: 100 μg/m3 8-hour mean
Nitrogen Dioxide NO2: 40 μg/m3 annual mean 200 μg/m3 1-hour mean
Sulfur Dioxide SO2: 20 μg/m3 24-hour mean 500 μg/m3 10-minute mean
18
EURO Engine Emission Standards - History and Latest
European emission standards for passenger cars g/km
Tier Date CO THC NMHC NOx HC+NOx PM P***
Diesel
Euro 1† July 1992 2.72 (3.16) - - - 0.97 (1.13) 0.14 (0.18) -
Euro 2 January 1996 1.0 - - - 0.7 0.08 -
Euro 3 January 2000 0.64 - - 0.50 0.56 0.05 -
Euro 4 January 2005 0.50 - - 0.25 0.30 0.025 -
19
Euro 5 September 2009 0.500 - - 0.180 0.230 0.005 -
Euro 6 (future) September 2014 0.500 - - 0.080 0.170 0.005 -
Petrol (Gasoline)
Euro 1† July 1992 2.72 (3.16) - - - 0.97 (1.13) - -
Euro 2 January 1996 2.2 - - - 0.5 - -
Euro 3 January 2000 2.3 0.20 - 0.15 - - -
Euro 4 January 2005 1.0 0.10 - 0.08 - - -
Euro 5 September 2009 1.000 0.100 0.068 0.060 - 0.005** -
Euro 6 (future) September 2014 1.000 0.100 0.068 0.060 - 0.005** -
* Before Euro 5, passenger vehicles > 2500 kg were type approved as light commercial vehicles N1-I
** Applies only to vehicles with direct injection engines
*** A number standard is to be defined as soon as possible and at the latest upon entry into force of Euro 6
† Values in brackets are conformity of production (COP) limits
Emission standards for light commercial vehicles
European emission standards for light commercial vehicles ≤1305 kg (Category N1-I), g/km
Tier Date CO THC NMHC NOx HC+NOx PM P
Diesel
Euro 1 October 1994 2.72 - - - 0.97 0.14 -
Euro 2 January 1998 1.0 - - - 0.7 0.08 -
Euro 3 January 2000 0.64 - - 0.50 0.56 0.05 -
Euro 4 January 2005 0.50 - - 0.25 0.30 0.025 -
Euro 5 September 2009 0.500 - - 0.180 0.230 0.005 -
Euro 6 (future) September 2014 0.500 - - 0.080 0.170 0.005 -
Petrol (Gasoline)
Euro 1 October 1994 2.72 - - - 0.97 - -
Euro 2 January 1998 2.2 - - - 0.5 - -
20
Euro 3 January 2000 2.3 0.20 - 0.15 - - -
Euro 4 January 2005 1.0 0.10 - 0.08 - - -
Euro 5 September 2009 1.000 0.100 0.068 0.060 - 0.005* -
Euro 6 (future) September 2014 1.000 0.100 0.068 0.060 - 0.005* -
* Applies only to vehicles with direct injection engines
European emission standards for light commercial vehicles 1305 kg – 1760 kg (Category N1-II),
g/km
Tier Date CO THC NMHC NOx HC+NOx PM P
Diesel
Euro 1 October 1994 5.17 - - - 1.4 0.19 -
Euro 2 January 1998 1.25 - - - 1.0 0.12 -
Euro 3 January 2001 0.80 - - 0.65 0.72 0.07 -
Euro 4 January 2006 0.63 - - 0.33 0.39 0.04 -
Euro 5 September 2010 0.630 - - 0.235 0.295 0.005 -
Euro 6 (future) September 2015 0.630 - - 0.105 0.195 0.005 -
Petrol (Gasoline)
Euro 1 October 1994 5.17 - - - 1.4 - -
Euro 2 January 1998 4.0 - - - 0.6 - -
Euro 3 January 2001 4.17 0.25 - 0.18 - - -
Euro 4 January 2006 1.81 0.13 - 0.10 - - -
Euro 5 September 2010 1.810 0.130 0.090 0.075 - 0.005* -
Euro 6 (future) September 2015 1.810 0.130 0.090 0.075 - 0.005* -
* Applies only to vehicles with direct injection engines
European emission standards for light commercial vehicles >1760 kg max 3500 kg. (Category
N1-III & N2), g/km
21
Tier Date CO THC NMHC NOx HC+NOx PM P
Diesel
Euro 1 October 1994 6.9 - - - 1.7 0.25 -
Euro 2 January 1998 1.5 - - - 1.2 0.17 -
Euro 3 January 2001 0.95 - - 0.78 0.86 0.10 -
Euro 4 January 2006 0.74 - - 0.39 0.46 0.06 -
Euro 5 September 2010 0.740 - - 0.280 0.350 0.005 -
Euro 6 (future) September 2015 0.740 - - 0.125 0.215 0.005 -
Petrol (Gasoline)
Euro 1 October 1994 6.9 - - - 1.7 - -
Euro 2 January 1998 5.0 - - - 0.7 - -
Euro 3 January 2001 5.22 0.29 - 0.21 - - -
Euro 4 January 2006 2.27 0.16 - 0.11 - - -
Euro 5 September 2010 2.270 0.160 0.108 0.082 - 0.005* -
Euro 6 (future) September 2015 2.270 0.160 0.108 0.082 - 0.005* -
* Applies only to vehicles with direct injection engines
Emission standards for trucks and buses
Whereas for passenger cars, the standards are defined by vehicle driving distance, g/km, for trucks they are defined by engine energy output, g/kWh and are therefore not comparable. The following table contains a summary of the emission standards and their implementation dates. Dates in the tables refer to new type approvals; the dates for all type approvals are in most cases one year later (EU type approvals are valid longer than one year).
The official category name is heavy-duty diesel engines, which generally includes trucks and buses.
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EU Emission Standards for HD Diesel Engines, g/kWh (smoke in m−1)
Tier Date Test cycle CO HC NOx PM Smoke
Euro I 1992, < 85 kW
ECE R-49
4.5 1.1 8.0 0.612
1992, > 85 kW 4.5 1.1 8.0 0.36
Euro II October 1996 4.0 1.1 7.0 0.25
October 1998 4.0 1.1 7.0 0.15
Euro III
October 1999 EEVs only ESC & ELR 1.0 0.25 2.0 0.02 0.15
October 2000
ESC & ELR
2.1 0.66 5.0 0.10
0.13* 0.8
Euro IV October 2005 1.5 0.46 3.5 0.02 0.5
Euro V October 2008 1.5 0.46 2.0 0.02 0.5
Euro VI 31. December 2013[19] 1.5 0.13 0.4 0.01
* for engines of less than 0.75 dm³ swept volume per cylinder and a rated power speed of more than 3,000
per minute. EEV is Enhanced environmentally friendly vehicle.
Sulfur in Liquid Fuels Mandatory environmental fuel specifications are introduced by EU
Directives. The following are the most important steps in the evolution of EU diesel fuel
specifications:
Effective 1994.10, a maximum sulfur limit of 0.2% (2,000 ppm) was introduced
for all gas oils, including diesel fuel. The minimum cetane number was 49.
1996.10: A maximum sulfur limit of 0.05% (wt.) = 500 ppm for diesel fuel.
2000.01: A maximum sulfur limit of 350 ppm and cetane number of 51 for diesel
fuel.
2005.01: A maximum sulfur limit of 50 ppm for diesel fuel for highway vehicles.
“Sulfur-free” 10 ppm sulfur diesel fuel must be available.
2009.01: A maximum sulfur limit of 10 ppm (“sulfur-free”) for diesel fuel for
highway vehicles.
This shows a 200 fold reduction in Europe in the allowable sulfur in diesel fuel over a
period of 15 years – a reduction of 99.5%! Specific fuel consumption did not change over
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this period so the amount of SO2 emitted relative to the amount of CO2 fell by a factor of 200
in those 15 years. Dramatic! In the 1980s sulfur in diesel was often about 1% (10,000 ppm) so
the reduction of SO2 relative to CO2 is around 1,000 fold now as compared to then.
PM10 (RSP) in urban centres over 100,000 population in micrograms/m3
Source: World Bank Development:
Sudan 246 (Highest - worst)
Pakistan 180
India 89
China 87
Iran 71
World Average 56
Hong Kong 52 (Not listed. Mean of general and roadside per EPDHK in 2010)
South Korea 43
United States 25
WHO guideline 20
United Kingdom 19
Australia 18
France 16
Belarus 8 (Lowest - best)
In this case Hong Kong is slightly better than the world average but is still 2.6 times the
WHO guidelines.
NOx Emissions - World Comparison Map
Source: http://www.eldoradocountyweather.com/climate/world-maps/world-nitrogen-dioxide.html Data
is the average for the month of March 2012.
24
The map above and the map following make it clear how high is the concentration of NOx in
Hong Kong itself and in parts of the adjacent land of China.
In passing, it is worth noting that CO2 is at almost the same level all around the world but it
never causes air pollution. The contrast with NO2 and SO2, which both produce severe
pollution in their respective ‘hot spots’, is very marked.
Source:
http://www.temis.nl/products/no2.ht
ml
“The yearly averaged tropospheric NO2
column measured by SCIAMACHY for 2004
in China. High values are measured above
the major cities. The industrial area around
the Yellow River (Huang He) is also
noticeable and highlights the river
stream.”
Hong Kong is shown near bottom-centre of the map. 1015 molecules of NO2 seems huge in a
column only 1 cm2. The map shows that over Hong Kong there are actually 2 x 1016
molecules of NO2 in a column!
Hong Kong Air Quality Comparisons with WHO Guidelines and World Averages The WHO guideline for NO2 is 40 μg/m3 annual mean. This compares with the EPDHK figures for 2010 as follows: WHO guideline NO2 40 μg/m3 HK NO2 general 52 μg/m3 HK NO2 roadside 114 μg/m3
HK NOx general 94 μg/m3
HK NOx roadside 318 μg/m3
The very high levels of nitrogen oxides in Hong Kong by world comparison on the one hand
and relative to the WHO guidelines on the other are apparent. The roadside levels in Hong
Kong are 2 to 3 times the general levels. This shows that road vehicles are the main source of
Nitrogen Oxides.
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Piston Engines and Fuel Comparisons
Some say, ‘diesels pollute, let’s just get rid of them’. They are less clear on what would take
their place. Without sophisticated emission controls diesels do indeed pollute but the answer
is keep them and provide controls. Spark ignition engines without emission controls also
pollute but good controls in the form of three-way catalytic converters have been in general
use for two decades or so.
CR Fuel Hyundai I30 manual I30 Capital Cost
Compression
Ignition 17:1 Diesel 4.5l/100Km AU$23,090
Spark 10:1 Petrol 7.2l/100Km AU$19,590
Ignition 10:1 LPG* 11l/100 Km Add AU$4,000
13:1 CNG Not available but a possible option on buses or trucks
* LPG is often much cheaper per litre than petrol so fuel cost/Km is often lower with LPG.
The fuel efficiency of any piston engine rises as the compression ratio rises. The production
of NOx/NO2 also rises as compression ratio rises and this must be removed from the
exhaust. One great merit of diesels is their fuel economy. There used to be a further
advantage in that diesel was cheap relative to petrol but that is seldom so today. Diesel
engines are also reliable and have a long life – a diesel taxi or truck may run for 1 million Km
before replacement. A diesel does need more skilled and somewhat more expensive
maintenance than a petrol engine. Capital cost is somewhat higher.
The bus companies, for example, might choose to meet the higher standards by adopting
CNG fuel.
From EURO I to EURO VI permissible PM has been reduced by 61 fold and NOx by 20 fold.
The reductions relative to pre-EURO emissions are at least double that.
This measurement of engine pollutants per KWhr is equally applicable to engines which are
in trucks, earth-moving equipment, cranes, generators, airport handling machines, vessels,
ferries or the like. The HK emissions standards will apply across the board to all diesel
engines in HKSAR.
Note that measurements of Lead Pb and Sulfur S are absent. This is because they are
controlled by very strict limits on how much may be in the fuel – effectively none. Thus it is
26
not necessary to specify emission limits from engines. The limits are on the fuel going in,
which controls the exhaust coming out.
EEC study 2007: Sales weighted average cost per diesel vehicle (2005 prices)
EURO 6 EUR 5 EUR 4
PM mg/Km 5 5 25 NOx mg/Km 75 200 250 Cost above EURO 4 € 590 € 377 € 0 Cost above EURO 5 € 213 € 0 N/A
Costs of EURO VI Compliance for Vehicle and Plant Owners
Please see the website below for details of costs for a wide range of vehicle sizes when
moving from EURO IV (the present HKSAR standard) to EURO VI.
http://ec.europa.eu/environment/air/pdf/euro_6.pdf
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Questions and Answers on Hong Kong’s Air Quality
Q. Why is Hong Kong often covered in SMOG?
A. Mainly because of pollution from internal combustion engines - in vehicles, in plant used off-road and in vessels on the waters of Hong Kong. Removing that pollution, PM and NOx specifically, will clear Hong Kong’s SMOG. Failure to do so will keep the SMOG.
Q. How does Hong Kong’s air quality compare with that in the rest of the World?
A. That depends on the pollutant. For SO2, which is a very damaging pollutant in some countries, Hong Kong does very well indeed. SO2 pollution is only 1/5th of the World average and only half the strict WHO (World Health Organisation) guidelines. This is a splendid result. RSP (also called PM) in Hong Kong is slightly less than the World average but exceeds the WHO guideline by 160%. RSP (PM) must be reduced by a factor of 3 to come comfortably within the WHO guideline. NOx and NO2 in Hong Kong are altogether excessive by international comparison or by WHO criteria. These pollutants are prime producers of photochemical SMOG and reducing them drastically is the key to having good air quality in Hong Kong. Diesel engines, particularly older ones, are the main emitters of NOx and NO2. NOx needs to be cut back severely – particularly by the roadside where levels are even higher than they are generally.
Q. What about the power stations?
A. The power stations do produce most of the SO2 in Hong Kong’s air but, as above, the total amount of SO2 is well below the WHO guideline and is excellent by international comparisons. The power stations have made an outstanding job of cleaning up their emissions - especially given that they use about 11 million tons of coal. see: http://www.indexmundi.com/energy.aspx?country=hk&product=coal&graph=consumption
Q. Can’t pollution from vehicles be cleaned up? Why is that not done in Hong Kong?
A. Yes, pollution from vehicles can be cleaned up and this is done in other places by
imposing strict regulations. The regulations presently imposed in Hong Kong are not strict
enough to achieve clean air. The standards for new engines are below international best
practice and this needs to be changed. More important still is the need to upgrade or remove
the many dirty old engines on the roads, work sites or waters of HKSAR.
There is very high consumption of oil fuel in a compact area by many vehicles with poor emission standards (EUROIII to pre-EURO) so that it would be strange indeed if the result was not air pollution. It should be no surprise whatsoever that Hong Kong gets a lot of SMOG from diesel and, to a lesser extent, petrol engines.
28
Q. In Hong Kong smoke often blows from ferries and other vessels in the Harbour over
Central Hong Kong. How will controls on vehicles stop that?
A. Hong Kong’s own emission standards, HK1 to HK6, will include ALL diesel engines
used in HKSAR including ferries and other local vessels. The emission standard for heavy
diesel trucks is per KWhr of power output and that standard can readily be applied to
engines in vessels, on construction sites and in other non-road uses. The HK standards will
so apply it.
Q. Is it carbon dioxide in the air that causes pollution?
A. No. Carbon dioxide, CO2, is an invisible, tasteless, odourless, harmless gas which has
nothing whatsoever to do with SMOG or pollution in the streets of Hong Kong or elsewhere.
Pollutants, not CO2, cause SMOG. Reducing CO2 will not improve air quality in the least.
Q. But doesn’t removing CO2 remove the nasty, polluting chemicals?
A. No. Whenever any fuel - coal, diesel, petrol or natural gas - is burned a fixed amount of
CO2 is produced for each Kg or litre of fuel used. The nasty chemicals can and should be
removed by using the best available technology to filter them out or to convert them into
CO2. Indeed producing a little more CO2 is often the way to achieve large reductions in
harmful emissions; e.g. when PM (smoke) emission is catalytically converted to benign CO2.
CO2 is not a proxy for air pollution.
Q. Why do new cars carry windscreen stickers giving the emission of CO2 as well as fuel
consumption if CO2 does not measure pollution?
A. Why indeed! When fuel consumption is given it is redundant and pointless to give CO2
emission also. For any given fuel – CNG, LPG, petrol or diesel - and quite irrespective of the
make, design or age of the vehicle, fuel consumption and CO2 emission move inexorably in
lockstep. For example a petrol engine which uses 10 litres/100 Km always produces 232
grams of CO2 per km – and pro rata up and down the consumption scale. A diesel with the
same consumption always produces 265 grams of CO2 per km and pro rata (but a diesel will
use much less fuel for a given task). It makes sense to give fuel consumption or CO2 but not
both.
Q. Why do vehicles not carry a sticker showing the amount of real pollutants such as PM
and NOx?
29
A. Why not indeed! This curious omission, which applies around the world and not only in
Hong Kong, is one of life’s little mysteries. For HKSAR a statement of the PM and NOx
emissions per km would be of critical relevance to Hong Kong’s air quality. They vary
greatly relative to fuel consumption depending on the make, design and age of the vehicle.
The emissions of PM and NOx should replace CO2 on windscreen stickers.
Q. Surely if we stopped burning coal, diesel, petrol and other fuels we would get rid of the
nasty chemicals?
A. Yes; but that is not all we would get rid of. We would have no electricity and no rail, road
or sea transport for starters. Jobs would be few and far between. Life in modern Hong Kong
depends crucially on energy, especially electricity, from burning fossil fuels. We need to
continue using the fuel but to clean up the resultant exhaust gases thoroughly. The power
stations have already shown how well this can be done while generating very large amounts
of reliable power at reasonable cost.
Q. If all the vehicles in Hong Kong were electric would that stop the pollution?
A. Yes – provided all other engines such as those on construction sites and in ferries were
also electric. Hopefully that will happen one day but realism is also needed. If Hong Kong
has to wait for clean air until most of its heavy vehicles and vessels are electric, the wait will
be of unconscionable duration.
There is a good case today for going over to electric-hybrid taxis rather than using LPG.
Q. Why can’t we go all-electric right now?
A. Because all-electric heavy trucks are not available anywhere and because the relatively
small electric cars that are available are very expensive and have limited range. At present,
all-electric is a non-starter for ferries and other vessels. Electric vehicles are 0.03% of the total
vehicles in Hong Kong today.
Source: Hong Kong Economic Journal, 9 Aug 2012.
'Electric car technology has not arrived'
“Based on Nomura's discussion with industry players, the existing battery technology
cannot meet consumer requirements. Electric vehicle technology today is not mature enough.
Rechargeable batteries for electric cars are still bulky, heavy, costly, low capacity; it may be
quite a while before a meaningful electric vehicle market can be developed”.
30
Q. Is there something wrong with having an electric vehicle?
A. Certainly not. They are most welcome wherever owners find they make economic sense
but owners must accept a ‘level playing field’ with others as regards Government help.
They will have the benefit that excise is not applied to their ‘fuel’.
Q. Would air quality be improved if road congestion in Hong Kong were reduced?
A. Yes, it certainly would - and there are many other benefits from reduced road congestion.
However, big cities around the World have tried without success to cut road congestion.
With ever more vehicles trying to use the same amount of road, congestion tends to get
worse and not better. So by all means try to reduce congestion but never be misled in
thinking that this can be a substitute for the crucial task of reducing vehicle emissions.
Q. Those are things we can’t do; what can we do to get clean air?
A. Encourage the Government to legislate for World’s-best-practice emission controls on all
engines in Hong Kong and to enforce those standards strictly.
Q. What are those standards?
A. They are the European ‘EURO’ standards for vehicle emissions. Hong Kong presently
requires EURO IV. The latest standard is EURO VI and Hong Kong should, after a
reasonable period of grace, make its own, compatible standard – HK6 - mandatory for all
engines, especially diesels, operating anywhere in HKSAR. In applying to ALL engines,
whenever they were built and wherever they are being used, HK6 differs crucially from
EURO and from most national standards which apply only to new vehicles. HK6 will reduce
Hong Kong’s emissions sufficiently to make our air clean within an acceptable time period.
Q. Isn’t it risky for Hong Kong to have its own standards because they may not fit in with
the rest of the World?
A. Hong Kong’s HK standards will be set within the ‘envelope’ of World standards. This
will ensure that vehicles and engines which will meet Hong Kong’s requirements are
available internationally. The very highest standards must be mandated for controlling NOx
and PM. On the other hand Hong Kong will have flexibility to add to, omit or modify
requirements imposed by other countries to best meet the specific needs of HKSAR. Hong
Kong will be able to apply the standards to all engines.
31
Q. How do emissions of older trucks, say 1990 vintage, compare with HK6 trucks?
A. With HK6 the nasty emissions of NOx and PM for a given size of truck are reduced by
about 98% relative to 1990, i.e. from 100 units to 2 units. This means that one 1990 model
truck emits as much nasty stuff as 50 HK6 trucks. Getting the old and dirty trucks off the
road is crucial to giving Hong Kong clean air. The same applies to old and dirty diesels used
off-road or on the seas of Hong Kong.
Q. These very clean new trucks and engines sound too good to be true. Are they real or are
they just ‘pie in the sky’?
A. They are very real. Many are already being made by companies such as Mercedes-Benz,
Fuso, MAN, SCANIA, Cummins (engines built in Beijing), Detroit Diesel, IVECO, Guangxi
Yuchai and are in service. They deliver what they promise. The European standards require
that each truck can maintain its pollution control over a life of 700,000 kms and HK6 will
demand the same.
Q. When and how should Hong Kong implement HK6?
A. It should start in 2013 and be fully implemented by 31st December 2018. It should then
cover all new and existing engines e.g. cars, trucks, buses, tractors, generators, construction
plant, ferries, other vessels, etc. The important thing is that when the change is completed it
covers all new and existing engines, is strictly applied and works consistently. The process
will be progressive from 2013 onwards.
Q. What has Hong Kong already done to improve air quality?
A. Some very good things have been done especially in the power stations. This has reduced
harmful SO2 emissions to half the World Health Organisation (WHO) guidelines and that is
impressive. Mandating ultra-low-sulfur (ULS <10 ppm sulfur) diesel fuel for road use is
really good. This allows the devices which remove NOx (Selective Catalytic Reduction -
SCR) and PM (Diesel Particulate Filter - DPF) to work at their very best. It is an important
enabler for applying HK6 to diesels effectively. ULS diesel (<10 ppm sulfur) should be made
mandatory for ALL diesel engines in Hong Kong – especially for ferries.
But action has not gone nearly far enough. The level of SMOG-producing, eye-watering
roadside NO2 and NOx is way above the WHO guidelines and international comparisons.
Q. There are over 600,000 vehicles in Hong Kong; surely it will be far too expensive to
replace them, plus the non-road diesel engines, by the end of 2018?
32
A. The widespread benefits from better air quality will be so large that even such a huge
expense would be worthwhile but, happily, many vehicles will not need to be replaced but
merely upgraded. For vessels such as ferries, engine replacement alone will be needed. This
will much reduce the cost. Many cars and taxis (EURO IV or better) will be able to meet HK6
with correct tuning, good maintenance and upgrading of the catalytic converters in their
exhausts. What will need removal, or the fitting of new engines, are the old and dirty diesels
– pre-EURO IV. It is crucial that they are upgraded or taken out of use. Newer trucks, buses,
diesel-powered plant and vessels can meet HK6 by retro-fitting SCR and DPF units.
Q. That will still be pretty expensive. Who will pay?
A. The owners of the vehicles, plant or vessels will pay to improve their own engines. No
one has a right to hazard the health and well-being of their fellow citizens in the course of
their personal or business life. All those who are doing so now have a moral duty to stop it
and clean up their act. The HK standards will make that a legal duty also.
Q. Should the Government help vehicle owners?
A. Yes, but only in cases of genuine hardship. In this context hardship means a threat to
employment or livelihood. It does not mean mere cost or inconvenience.
Q. Does CNG – compressed natural gas – have a part to play in Hong Kong?
A. In principle, yes. It is easier for a big truck or bus to meet HK6 using CNG fuel than
using diesel. Some bus fleets in the USA are already achieving the equivalent of HK6 by
using CNG fuel. A CNG engine is similar to a diesel but has spark ignition, a lower
compression ratio and other detail differences. Singapore presently offers incentives for
vehicles using CNG. The downside in Hong Kong is that there is a not a suitable CNG
supply infrastructure at present. As and when that changes, CNG may have an important
role in helping to clean the air of Hong Kong.
Q. Some countries have a phone, SMS and email hotline to report dirty or smelly exhausts –
with or without a confirmatory photo. Would that work in Hong Kong?
A. Yes, and the sooner the better.
Q. Diesels seem to be the main problem. Why not get rid of them altogether?
33
A. Because they are far too useful. Around the world almost all trucks now have diesel
engines for very good reasons. They are cost-effective prime movers, economical on fuel,
have high torque which gives good lugging power for heavy loads and steep hills, have a
long range, are reliable and last well. Hong Kong will need diesel engines for many years to
come.
Q. Emissions may be low when vehicles or engines are new. But what will happen as they
get older?
A. Constant checking will be needed. HK6 will match EURO VI in requiring standards to be
maintained for 700,000 kms of use. The Government will need to beef up emissions testing
both on an annual basis and with random checks. After 2018 any non-compliant engine will
summarily be taken off the roads, work-sites or waters of Hong Kong unless and until it
does comply. Fines for breaches of emission regulations will also be imposed. These fines
will resemble, but be much heavier than, those imposed for littering and other anti-social
behaviour on the streets of Hong Kong today.
Q. These proposals may be satisfactory for vehicles registered in Hong Kong but what about
badly polluting trucks coming into HKSAR to bring goods from elsewhere?
A. The Hong Kong Government will require such trucks to conform to Hong Kong’s
emission regulations. The Government may choose to institute a ‘certificate of compliance’
which each truck coming into HKSAR must possess.
Q. What about the pollution which blows over Hong Kong from elsewhere?
A. Unfortunately Hong Kong is stuck with that – at least for the time being. During autumn
and winter, winds in Hong Kong are from the North for about 20% of the time and that
carries pollution from the mainland to HKSAR.
http://www.hko.gov.hk/cis/normal/1971_2000/normals_e.htm#table7
The prevailing Easterly and Southerly wind in Hong Kong comes from the ocean and brings
clean air so then Hong Kong’s citizens can see that their own air is really like. After 2018
Hong Kong will enjoy pristine air and pass it on to its neighbours. That fine example will
surely be rewarded and reciprocated.
Q. What about CCS – Carbon Capture and Storage for Power Stations?
A. CCS for power stations is a seductive trap which is as ineffective as it is expensive. Even
in the improbable event of CO2 capture being successful, less CO2 will do nothing to
34
improve the air quality of Hong Kong. Hong Kong should avoid CCS like the plague. There
are abandoned CCS projects all around the world. See CCS problems and failures on page
52. There are no CCS schemes operating on a full power station scale, or anything
approaching full scale, anywhere.
Q. How quickly can we get much better air quality?
A. In about six years. To get swift improvement it is more urgent to turn Bad into Good than
Good into Very Good. Any engine which pollutes badly should be pinpointed and not
permitted to remain in use in Hong Kong for a day longer than necessary. After 2018 it will
be HK6 Very Good all round. That is an ambitious but attainable time scale.
Q. Is there a Cost/Benefit analysis for this air quality improvement?
A. Yes. Each time the EURO authority proposes tighter emission standards they have to
present an Impact Statement which includes a cost/benefit analysis for the intended change.
The cost/benefit analysis is set out at (and in many related links):
http://europa.eu/legislation_summaries/environment/air_pollution/l28159_en.htm
In summary, it finds that costs of €7.1 billion per annum will lead to savings of €42 billion
per annum: a very high cost benefit ratio of +6. This applies in Europe where no cities now
experience the damaging SMOG which is still frequent in Hong Kong. Given that Hong
Kong is starting from a condition of frequent SMOG, the C/B ratio of corresponding air
quality improvements in Hong Kong will surely be even higher than the excellent figure of
+6.
Q. Is it good policy for the people of Hong Kong to spend six years, much hard work and
considerable sums of money to implement HK1 to HK6 and achieve really clean air?
A. Yes!
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Improving Air Quality in HKSAR – Technical Report
References in the Report
Throughout this report extensive use is made of the excellent material published by the
HKSAR’s Department of Census and Statistics. Almost all Hong Kong-specific data is from
this source with calculations as appropriate. USA energy data is from the US EIA. The WHO
data is from its website. This basic data is grouped together at pages 7 to 25 above.
Fuel Use in Hong Kong
Populous, prosperous and compact Hong Kong needs a lot of electricity and a lot of
transport. In turn this needs coal for the power stations and oil fuel (mainly diesel) for the
vehicles. Given Hong Kong’s total area of 1,104 Km2 this means that every single day Hong
Kong burns some 26 tons of coal for each 1 Km2 and nearly 5 tons of diesel oil per Km2. It
sounds huge and it is. The equivalent numbers in the energy-intensive USA, for example, are
0.3 tons of coal and 0.3 tons of total oil products per day for each Km2. With so much fuel
being burned, keeping the air clean and maintaining the age-old tradition of “The Fragrant
Harbour” is a big task, so;
A decision by the HKSAR Government to achieve progressively higher air quality
standards moving NOx and PM emissions towards and then ahead of the World Health
Organisation (WHO) guidelines is the key to giving Hong Kong really clean air.
Skilled deployment of existing top technology will solve the problem at reasonable cost
and reasonably quickly – extravagant measures such as a major move to hybrid or electric
vehicles are not needed. They would divert resources and so slow the change to clean air.
The power station example should be rigorously applied to all sources of air pollution across
the whole HKSAR with the aim of bringing each scheduled air pollutant in HKSAR below
the WHO guidelines. It is for the Government to set achievable high standards and
enforce them and for users and operators to choose how they will meet and pay for them.
NOx in Exhaust Gas
Burning anything needs oxygen, i.e., air. Air is about 78% nitrogen and the high
temperatures of combustion in a piston engine make the Nitrogen (N2) and the Oxygen (O2 -
21%) combine to form various oxides of nitrogen (NOx). These oxides of nitrogen are toxic
and harmful in their own right and can form SMOG. In strong sunlight they may create
36
Ozone (O3) which is likely to form photochemical SMOG. The term SMOG means ‘Smoky
Fog’ – when it was originally coined a century ago the SMOG agent was mainly SO2; in
Hong Kong today it is mostly NOx and NO2.
It is of critical importance to reduce the amount of NOx emitted on the roads of Hong
Kong. Progressively upgrade or remove the worst vehicles and engines.
Ozone Formation near the Ground
When it is high in the stratosphere, Ozone (O3) protects us from excess UV rays – the kindly
‘Ozone Layer’. At ground level, however, it causes smog and itself is very unpleasant and
bad for health. It is also harmful to growing plants. Thus O3 is correctly classed as an air
pollutant when present near the Earth’s surface. The chemical reaction whereby NOx
produces O3 can go both ways. When NOx is low (within the WHO guidelines) very little O3
is formed. As the level of NOx rises high above WHO, ever more O3 forms. However when
NOx rises still further to extreme concentration it destroys O3. Thus the negligible levels of
roadside O3 in Hong Kong reflect the extremely high level of NOx. It is bad, not good. It
leads to the formation of very harmful PANs and to their version of eye-watering SMOG.
Carbon Monoxide – a Killer
If combustion in an engine is not complete, carbon monoxide (CO) is formed. It is fatal at
over 0.08% in the air. There is about 0.7% of CO in the exhaust gas leaving a gasoline or LPG
engine but nowadays this is reduced to a small fraction of that - being converted to benign
CO2 by the catalytic converters now fitted to petrol or LPG cars.
VOC – Volatile Organic Compounds – also called HC
These cover a wide variety of low boiling point hydrocarbons; from spilt and evaporated
petrol to obscure, special-purpose chemicals. Vehicles produce VOC’s and so do trees and
shrubs. VOCs may be directly harmful and may, by reaction with NOx in sunlight, promote
O3 formation. They are harmless when fully converted to CO2; for example, by catalytic
converters in cars. It is more effective to remove SMOG by reducing NOx than by trying to
reduce VOCs.
WHO Guidelines for Air Quality
In Hong Kong today, measurements show that the level of NOx and RSP (PM) are far above
the World Health Organisation (WHO) guidelines. The health, well-being and amenity of 7
million people require that they be brought within the WHO guidelines. The HKSAR
37
Government has made consistent and strenuous efforts over decades to improve the air
quality in Hong Kong. Despite this good work, reputable newsagencies such as Reuters
report that air quality in Hong Kong has deteriorated over the past decade.
The ‘big ticket’ item in Hong Kong’s air pollution today is exhaust from diesel engines –
especially old ones – EURO III and lower.
Diesels are marvellous engines with high power, good fuel efficiency, excellent reliability,
long life and sustained pulling power for heavy loads of all kinds. The answer is not to stop
using them but to clean up their exhausts. They should be cleaned to the extent needed to
make their emissions consistent with Hong Kong meeting the WHO guidelines. It makes no
sense to go with half measures at this stage. Improvements in other, less emission-intensive,
sectors are always welcome but must not divert attention from the critical main game. Just as
for power stations, there are several technologies which yield clean running diesels. The 6-Rs
for clean diesels are below:
The 6 R's of Diesel Clean Up:
Refuel; Retrofit; Repower; Replace; Repair; Rebuild.
This report recommends that the Hong Kong Government motivates users and operators of diesel engines to clean up their act as necessary by using one or more of the above methods. The motivation should be by setting strict emission standards together with comprehensive and rigorous enforcement. Any vehicle, plant or vessel in Hong Kong which fails to meet the standards required by the required date in the HK1 to HK6 schedule should be taken off the roads, work sites or waters of Hong Kong unless and until it does so.
The Power of Hong Kong’s Example to the World
From the end of 2018, Hong Kong’s clean air will match its already clean streets and will be
an exemplar of health, well-being and high amenity to big cities right around the World.
Cost Benefit Analysis
Whenever the EURO authority proposes tighter emission standards they must present an
Impact Statement which includes a cost/benefit analysis of the intended change. The C/B
analysis and many related links are at:
http://europa.eu/legislation_summaries/environment/air_pollution/l28159_en.htm
38
It finds that costs of €7.1 billion per annum will lead to savings of €42 billion per annum: a
very high C/B ratio of +6. This applies in Europe where no cities now experience the
damaging SMOG which is still frequent in Hong Kong. Given that contrast, the C/B ratio of
corresponding air quality improvements in Hong Kong will be at least as high and probably
much higher.
Wind Borne Pollution from Neighbours
One obstacle to achieving clean air is pollution coming from neighbours. When the wind is
from the north or the west, pollution from the mainland may blow over Hong Kong.
However, the wind in Hong Kong prevails from the East and South-East which is from the
open sea with negligible pollution. Therefore pollution from elsewhere should not be a
reason to hold back on giving Hong Kong itself the World’s cleanest urban air. Whenever
the prevailing wind blows or when it is calm the people of Hong Kong will be able to see
just what their air really looks like. They can take pleasure in passing pristine air on to their
neighbours and in setting them a fine example.
Vehicle Pollution from Neighbours
This is a very different issue. If vehicles from
outside Hong Kong with poor emission
controls enter HKSAR, just one of those
vehicles can cause more air pollution in Hong
Kong than many local vehicles with good
emission equipment. To give Hong Kong
cleaner air it is essential that vehicles entering
HKSAR be routinely checked for the
cleanliness of their exhausts and that entry be forbidden if they do not meet HKSAR
standards.
The photo shows one of the things that London did in this respect prior to the 2012
Olympics. Something similar might be appropriate permanently at entry to HKSAR?
It might be argued that, notwithstanding its small land area, Hong Kong is surrounded on
three sides by sea and so the product of the burnt fuels can disperse over the ocean. When
the wind blows that is true but that is not when pollution is critical. Critical pollution occurs
on calm, hot days and then it stays right on top of the land of Hong Kong and its 7 million
people. Furthermore the density of high buildings in Hong Kong is such that there can be a
stiff breeze on the coast but calm in the City Centre.
Because HKSAR has probably the most intense concentration of diesel burn in the World it
follows that if it is to match, let alone better, the air quality elsewhere Hong Kong’s
emission standards need to be stricter than elsewhere. In that Hong Kong adopts emission
39
standards developed elsewhere, i.e. USA, EEC and Japan, it must, as a minimum adopt the
latest and best standard. It should be strict in imposing this standard on all emissions
whether from new or old vehicles and whether a vehicle is based in Hong Kong or
elsewhere. It must also apply to all engines, on-road or off. So: control all emissions from
all engines anywhere in HKSAR.
Daily variations of ground ozone and temperature at meteoLCD station - Meteorological Station of the
Lycée Classique de Diekirch, L uxembourg
The odd-man-out in the HKEPD graph on page 15 is Ozone
(O3) at the roadside. It “not measured because of very low
concentration”. The graph opposite shows that O3 typically
has a very strong diurnal variation. It increases in response to
sunlight and falls off in darkness. In the example opposite
the O3 level measured at 6 am is negligible but at 6 pm is
about 120 μg/m3. The 8-hour average between midday and 8
pm is around 100. The measurement of O3 needs to be
positioned and timed so as to detect peak levels. It is short
term peaks of O3 that cause smog – not the long term average
and these may initially increase as the now extremely high
NOx level at roadside falls.
The Hidden Enemy - PAN - Peroxyacyl Nitrates
When there is a high level of NOx and VOCs these two react under strong sunlight to release a free Oxygen atom (O). This then combines with an oxygen molecule to give Ozone O3 which is toxic to humans and plants and is a common component of photochemical smog. It seems from the absence of roadside O3 that this is not the case in Hong Kong. But there is often smog so where does it come from?
When the level of NOx is extreme, rather than just high, the reactions take a different path. The excess NOx captures the Oxygen atoms before the Oxygen molecules (O2) do and converts itself to NO2.
NO + O NO2
This accounts for the negligible level of O3 where there is an extreme level of NOx. Although that sounds like good news it is not. With extreme levels of NOx, in strong sunlight a different reaction between the VOCs and NO2 happens and very unpleasant PANs are produced.
CH3C (O)OO· + NO2 → CH3C(O)OONO2
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PANs, Peroxyacyl Nitrates (also known as APNs), are powerful respiratory and eye irritants. They are produced by the gas-phase oxidation of a variety of volatile organic compounds (VOCs), or by aldehydes and other oxygenated VOCs oxidizing in the presence of NO2. The final step is a combination of a peroxyacyl radical and NO2 for example, peroxyacetyl nitrate CH3C (O)OONO2 as above. PANs are toxic and irritating because
they dissolve more readily in water than Ozone O3. They are lachrymators, causing eye irritation in concentrations of only a few parts per billion. At higher concentrations they cause extensive damage to human tissue and vegetation. Both PANs and their chlorinated derivatives are said to be mutagenic; that is, they can cause cancer – especially skin cancer.
The current negligible level of roadside O3 together with frequent smog is a warning sign
that the level of PANs need close monitoring. The action needed to cure the problem is a
drastic reduction in NOx. As NOx levels come down there will be a temporary rise in
roadside O3 until it subsides again when NOx gets really low. That will mark a major
achievement in Hong Kong’s advance to really clean air.
Sulfur Dioxide (SO2) - a Success Story
The SO2 levels shown on the EPDHK graph are comfortably and commendably within the
WHO guidelines. They are less than half the world average and reflect the costly and
comprehensive emission control programs of the electricity generating authorities and, to a
lesser extent, the use of ultra-low-sulfur road diesel. They show that the electricity
generating utilities have ‘done their bit’ in Hong Kong’s air pollution battle. No doubt they
will be vigilant to ensure that the high standards are maintained.
Castle Peak Power Station - Clean Air Retro-Fit
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“1. Boosted Over Fire Air (BOFA) -- Suppress formation of NOx
NOx is produced when nitrogen and oxygen combine during combustion. BOFA aims to change and optimize combustion of coal so as to suppress formation of NOx during the combustion process and reduce NOx emission. Installation of BOFA equipment in power generating units involves a lot of complex retrofit work and requires 500 tonnes of steel. After retrofitting, BOFA equipment is a part of the coal-fired boiler. 2. Selective Catalytic Reduction (SCR) -- Turn NOx in the flue gas into water vapour and non-toxic nitrogen gas Flue gas passing through BOFA moves on along the ductwork to the next emissions removal process. Passing through the SCR equipment which makes use of chemical reaction of Ammonia (NH3) and NOx, NOx in flue gas is converted into water vapour and non-toxic nitrogen gas and become part of the constituents of normal breathing air. NOx emission in the flue gas is further reduced upon processing of SCR. 3. Flue Gas Desulphurization (FGD) -- Remove SO2 from flue gas After removing NOx through BOFA and SCR, the flue gas is transmitted to an absorber tower, in which the flue gas is sprayed and reacted with alkaline limestone slurry. During the process, SO2 in flue gas is neutralized by limestone to form gypsum, a useful construction material. Meanwhile, RSP, which has been 99% removed by the electrostatic precipitator, is also further reduced in the process of desulphurisation. By-product of the Project - Gypsum The EC Project brings along additional environmental benefits. Gypsum, a by-product of the desulphurization process, is recycled for making cement and other construction material. Since the phasing-in of three units, nearly 30,000 tonnes of gypsum have been produced by the Project during the past few months.”
Lead (Pb) - another Success Story
Thirty years ago tetra-ethyl-lead was a routine additive used to improve the octane rating of
petrol (gasoline). Lead is a serious air pollutant which is especially harmful to children’s
development. Towards the end of last century leaded petrol was phased out completely and
so lead is no longer a significant air pollutant – except in the vicinity of lead-zinc mines.
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Diesel fuel does not contain lead and never did. The level of lead in Hong Kong’s air is now
well below the WHO’s tight guidelines. This is admirable.
The EURO vehicle emission standards do not list lead or sulfur. They control them via the
fuel by requiring that there shall be no lead and negligible sulfur going into vehicles’ tanks.
RSP (PM) and NOx from Vehicles, Plant and Vessels – a Sad Story
In contrast to the happy story on SO2 and Pb, RSPs in general and at the roadside are 125%
and 200% respectively above the WHO guideline of 20 μg/m3 for PM10. If most of Hong
Kong’s RSPs are in the (tiny) PM2.5 category they are even further over the WHO guideline.
As the maps and tables above show, NO2 is above the 40 μg/m3 annual average in the WHO
guidelines and NOx is at the very top end of the World scale. No wonder there are air
pollution problems in Hong Kong!
It is apparent from press reports and from general observation, that the people of Hong
Kong sense that their air quality is getting worse and not better. The Consultative Document
on Air Quality issued in 2009 showed that while the officially recorded level of air pollutants
was getting steadily less, the air quality of Hong Kong (as measured by days of reduced
visibility) was getting steadily worse. The problem is NO2, NOx and RSPs. This turns the
focus onto vehicles, particularly those with diesel engines. But first a look at petrol and LPG
engines in cars.
Petrol and LPG Vehicles
Cars and taxis with petrol or LPG fuel in Hong Kong now have catalytic converters. They
remove CO and unburnt hydrocarbons by converting them into harmless CO2. Some have 3-
way catcons which also remove NOx. Good maintenance is vital for the effective working of
those converters. Engines need to be tuned to run consistently within a precise air to fuel ratio
for their TWCs (catalytic converters) to work at their best. This consistency is more readily
attained with a fuel injected engine than in one with a carburettor. If the fuel injection is
computer controlled that is better still.
Three-Way Catalyst: The three-way converter (TWC) has been the primary emission control technology on light-duty petrol vehicles since the early 1980s. The use of TWCs, in conjunction with an oxygen-sensor-based, closed-loop fuel delivery system, allows for simultaneous conversion of the three criteria pollutants, HC, CO, and NOx, produced during the combustion of fuel in a spark-ignited engine.
43
Diesel engines are now the main culprits in polluting Hong Kong’s air – especially in the emission of NO2, NOx and RSPs (PM). But they are also vital to the economy and effective functioning of Hong Kong. The answer: clean up their exhausts comprehensively.
The 6 R's of Diesel Clean Up
Refuel. A switch to cleaner fuels such as ultra-low-sulfur diesel fuel can achieve modest reductions in pollutants. HONG KONG has already done this with <10 ppm sulfur diesel.
Retrofit. Engines can be retrofitted with emission control devices that can reduce pollution by as much as 90%. In some cases the cost may approach that of fitting a new engine. Ultra-low sulfur fuel helps pollution controls to work well.
Repower. Installing a new low-pollution engine in an older chassis can allow a machine to run for many more years.
Replace. Replacing a vehicle or item of plant with a new, lower-pollution model ahead of schedule can result in substantial pollution reductions.
Repair. Performing routine maintenance can keep pollution rates at or near original levels.
Rebuild, When repair is no longer adequate to sustain top emissions performance an engine rebuild may be necessary. This costs around half that of providing a new engine.
The above actions are at least as applicable to engines in ferries and other vessels as to diesels on land.
See link below for strategies to reduce pollution from bus fleets.
http://www.unep.org/transport/pcfv/PDF/Retrofit.pdf
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Government Sets the Standards – Users Choose How to Meet the Standards
In the opinion of the authors the role of the Government here is to set standards and to enforce them vigorously. It is up to users and operators to choose what they will do to meet the standards – provided they do meet them and pay for doing so. There is technology already available to enable Hong Kong to meet WHO standards at reasonable cost. For diesel engines the two key technologies, DPF and SCR, are outlined below. They are:
Diesel Particulate Filters - DPF
Diesel is by far the dominant vehicle fuel used in Hong Kong. General use of DPF filters is one very good way to clean up Hong Kong’s diesels. This includes trucks and buses but also construction and land equipment, stationary engines such as generators or cranes and all diesel powered vessels operating in and adjacent to the Port of Hong Kong. Very roughly it costs HK$66,000 to retro-fit DPF on a big bus. New diesel trucks with state-of-the-art DPF are now widely available.
A neat DPF Retro-fit.
Regenerating Diesel Particulate Filter is standard equipment on this new GM Isuzu, 7.8
litre diesel truck.
These high efficiency ceramic filters
have extremely high capture rates (>
99%) for the black carbon portion of
diesel exhaust particulates. Studies
done by the EPA in the USA indicate
that the monetised health benefits
from fitting DPF filters to existing
diesel buses are up to US$16 for every
US$1 spent on vehicle upgrades. Ref:
UNEP “Cleaning up Urban Bus Fleets”,
2009.
45
Selective Reduction Catalyst – SCR – A Critical Technology for HKSAR
The DPF unit will remove particulates and also unburned hydrocarbons and VOCs emitted
from the exhaust. It will not remove nitrogen oxides, NO2 & NOx. This requires a further
unit – an SCR. The SCR can operate continuously and does not affect engine running. SCR
offers reduced NOx emissions and better fuel economy at the same time. The cleaning
process is triggered by ‘AdBlue’, a nontoxic solution of water and urea, which is injected into
the exhaust-gas stream in precisely metered doses. This produces ammonia, which reacts
with NOx in the SCR system to
form nitrogen and water. Thus the
exhaust consists of entirely
harmless gases already present in
clean air; H2O (as water vapour),
N2 (nitrogen as in the air) and CO2.
The rate of use of the additive
solution is about 1 litre to every 50
litres of diesel fuel. It is
replenished during a vehicle’s
scheduled servicing.
Ultra-Low Sulfur Diesel Fuel
Since 2007 all highway diesel sold in Hong Kong has met the <10 ppm sulfur standard. All
diesel fuel sold for use within Hong Kong for whatever purpose, including vessels
operating locally, should meet this standard. It is vital for the long-term effective working
of both DPF and SCR. (There was a diesel fuel called ULS introduced in 2001 which had <50
ppm of sulfur. It has been overtaken by the <10 ppm fuel. This makes little difference to SO2
emissions but is much better for DPF and SCR units and thus for PM and NOx emissions.)
Comparison with Diesel Oxidation Catalyst - DOC
Many diesel engines in Hong Kong are already fitted with the cheaper Diesel Oxidation
Catalysts. These DOCs do help but they only remove 25% to 35% of the particulates. This is
much inferior to the 90% to 95%, even 99%, reduction achieved by a modern, ceramic DPF.
DOCs remove up to 40% of the carbon monoxide and 50% of the unburnt hydrocarbons.
NOx or NO2 are not reduced.
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Diesel Retrofit Technologies
Source: http://www.dieselretrofit.eu/technologies.html
Emission control technologies include catalytic converters and particulate filters. They consist of a stainless steel box (or can) mounted in the exhaust system either as original equipment or retrofit emissions control device. In some retrofit applications, they can even be mounted in the original muffler.
Inside the can is an autocatalyst or a particulate filter. The autocatalyst can be a ceramic or metallic substrate with an active coating incorporating chemical compounds (the washcoat ) to support a combination of catalytic metals or minerals selected for their effectiveness in the required emissions reductions. It can also be a homogeneous honeycomb-ceramics in which only active compounds are extruded simultaneously. The autocatalyst or the particulate filter is mounted in a can and is protected from vibration and shock by a resilient 'mat'. The emission control device then looks similar to an exhaust muffler. Typical emission control devices available for retrofit applications are Diesel Particulate Filters (DPF), Diesel Oxidation Catalysts (DOC), and Selective Catalytic Reduction (SCR) catalysts. They allow the reduction of Particulate Matter
(PM) - soot particles - and NOx emissions from existing diesel
engines and vehicles.
Technology
Emission reduction potential
Particulates NOx
mass number
Wall-Flow Filter >95% >99% <5%
Partial Flow Filter 30-60
% <5%
Diesel Oxidation
Catalyst <25% N/A <5%
Selective Catalytic
Reduction <10%
>70%
(up to 95%)
Combined DPF+SCR >95% >99% >70%
(up to 95%)
Typical PM and NOx reduction potential for various retrofit devices.
Combined systems to reduce both PM and NOx simultaneously are also available. Fuel economy and CO2 emissions should not be negatively impacted by the use of a retrofit emissions control device provided the system is properly designed for the particular applications.
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DPF and SCR are not prescriptive
The purpose of describing PDF and SCR is to show that effective measures are available at
reasonable cost to give diesel engines very clean exhausts when coupled with <10 ppm
sulfur diesel fuel. It is for the Government to set and enforce the standards and for users to
meet them and pay for them as they think best. There may be other ways which will be
entirely acceptable provided they get the required results.
Hybrid powered taxis or buses and/or CNG fuel for buses and trucks are yet other
possibilities – provided the standards are met and the operators pay their own costs.
Installation, Maintenance and Testing - IMT
It will be important that good IMT facilities with well-trained operators are available in
ample time to install, maintain and test all those new devices carefully. This is a critical
issue and goes hand in hand with setting very high standards. The Government’s
responsibility is to ensure good testing to go with high standards and to fund this need. The
industry itself will, perforce, take care of the rest.
What Standards should be set?
Emission standards are complicated, with curious names and elaborate testing procedures.
These are needed to make the tests objective and reflect the real world as nearly as possible.
That being so many countries, including HKSAR, use standards developed elsewhere. The
main sources are the USA, the EEC and Japan. Hong Kong refers to all three.
In general, Hong Kong has chosen relatively undemanding targets. As an example; the USA
EPA Tier 2 refers to all vehicles up to 3.8 tons whether they use gasoline or diesel. Making
the requirements independent of fuel type is a good start. So is requiring that a bigger
vehicle emits no more pollution per km than a smaller one.
“From Jan 1, 2006, all new passenger cars with spark-ignition engines in Hong Kong must meet either Euro IV petrol standard, Japanese Heisei 17 standard or US EPA Tier 2 Bin 5 standard. For new passenger cars with compression-ignition engines, they must meet US EPA Tier 2 Bin 5 standard.”
Bin 5 is a low Tier 2 standard. The USA now specifies the higher Bin 2. Hong Kong always has to ‘try harder’ (never less hard) on air quality because of its huge fuel use relative to its compact geographic extent. See link below for an excellent modern study of diesel emissions and standards.
www1.eere.energy.gov/vehiclesandfuels/pdfs/diesel_technical_primer.pdf
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China Yuchai International Introduces First Euro VI Automotive Diesel Engine in China. Singapore, July 4, 2011
“China Yuchai” or the “Company”, announced today that its main operating subsidiary, Guangxi Yuchai Machinery Company Limited (“GYMCL”), recently introduced China’s first prototype diesel engine compliant with Euro VI emission standards. As China’s first Euro VI-compliant automotive diesel engine, GYMCL’s heavy-duty model YC6L-60 diesel engine has set another milestone in its history of technological achievement. At a press conference hosted by GYMCL at its offices in Yulin City, Guangxi Province, the National Passenger Car Quality Supervision and Inspection Center (Tianjin Automotive Test Center) released the test results of the YC6L-60 engine which was jointly developed over a four-year period, between GYMCL and researchers from Tianjin University’s National Key Laboratory of engine combustion. The results indicate that the nitrogen oxide emissions and particulate matter emissions of the YC6L-60 were well below the Euro VI emission requirements hence meeting the Euro VI emission standard. There are three key features of GYMCL’s YC6L-60 engine: (a) a proprietary low-temperature combustion technology which reduces the fuel injection pressure requirement hence improving the life span of the fuel injection system and other core parts of the engine; (b) the use of medium-intensity cooled exhaust gas recirculation (EGR) technology resulting in a clean and economic combustion process; and (c) the use of selective catalytic reduction (SCR) technology combined with diesel particulate filter (DPF) regeneration capability will reduce urea consumption during the after-treatment process resulting in cost savings to end-users. Since its introduction in the European Union (EU) in 2009, the Euro VI emission standard is, by far, the most stringent emission standard in the world. As the EU has announced plans to implement the Euro VI emission standards beginning in 2013, most European engine producers have been actively developing their products accordingly. The introduction of China’s first Euro VI-compliant diesel
engine by GYMCL demonstrates its world-class research and development capabilities”.
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Hong Kong has an international reputation for clean streets which are always kept litter-
free and clean. It is a proud and valuable reputation. It should be matched by equally
clean air. Clean air demands that stringent emission standards be set for all engines,
testing be rigorous and enforcement be firm.
Philosophy of Pollution Reduction
The posters above show the approach which Hong Kong takes to polluting litter, namely no
tolerance and on-the-spot fines. This approach is appealing, commendable and effective.
Many more countries should use it. The result is that Hong Kong has an international
reputation as a clean and tidy City. The authors believe and recommend that a similar
approach should be taken to achieving clean air – an even more important objective.
Thus the HKSAR Government should achieve high air quality by setting strict emission
standards for all equipment which emits exhaust. Regular and strict testing should be
instituted with on-the-spot fines for those breaching the standards.
The fines should be much higher than those for litter because, at hazard, is not only the
amenity of the people of Hong Kong but also their health and well-being. The fines should
be pro-rated according to the amount by which any vehicle or item of plant exceeds the
permitted emission level. The offending machine should be compulsorily withdrawn from
use unless and until it can meet the standards.
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Costs to Users and Operators
These strict standards will inevitably impose costs, inconvenience and sometimes hardship
on the owners and operators of polluting vehicles or plant.
Nobody has a right to hazard the health and well-being of their follow citizens in the
course of their business or personal activities. Polluting the air does just that and so it is
quite unacceptable. Competition will tightly constrain the extent to which resulting extra
business costs, where they exist, are passed on to customers.
Costs to Government
Costs to Government will come from establishing a stringent, widespread and random
pollution-testing regime. This will apply mainly to diesel engines but will also cover petrol
and LPG vehicles. Initially the budget for testing will need to be doubled and the number
of tests increased fourfold. These extra tests will be made possible by using best practice
methods. Experience in the field will show what further testing may be needed. There will
also be payments made by Government via the transitional ‘hardship’ fund.
The Pareto Principle and Pollution
Readers will be familiar with the ‘Pareto Principle’, often called the 80/20 rule. This says, for
example, that 20% of customers account for 80% of a company’s sales or that 20% of patients
account for 80% of visits to doctors’ surgeries. A similar principle applies to pollution from
vehicles.
100%
100%
80%
80%
60%
60%
40%
40%
20%
20%
0%
0%
Total Vehicles % Total Pollution %
This underlines the importance of targeting the vehicles or other engines which cause severe
pollution and giving priority to their early removal. It is a cost-effective way to tackle the
problem as those very polluting machines are typically old and of low value.
51
Some of those vehicles will be essential assets of small businesses and their removal may
threaten employment or livelihood. In that case this report recommends the Government
offer a ‘hardship’ payment. It will be for genuine hardship only – not for mere cost or
inconvenience.
CCS – Carbon Capture and Storage for Power Stations
This is one of the traps into which several nations have fallen and which we urge the
Government of Hong Kong to avoid like the plague! It is all cost, no benefit and final
abandonment. That has been the history of such schemes around the world. A CCS power
station scheme lasts as long its government subsidy and not a moment longer. Those who
advocate for power station CCS are invited to name one successful such plant in operation
capturing the full CO2 output from a power station. It can’t be done – there are none.
The following is from a broadcast by the Australian Broadcasting Corporation. It is
significant in its own right and more so because the ABC is typically a fan of all things
‘climate change’. In this case the facts worldwide speak for themselves.
Broadcast: 14/02/2012
Reporter: MICHAEL ATKIN
“Carbon capture and storage has been touted as one answer to climate change but is Kevin Rudd's
$300 million Global Institute providing Australian taxpayers value for money?”
JOSPEH ROMM, CENTRE FOR AMERICAN PROGRESS: “No one has put all the pieces
together into one commercial effort - have it run, kick the tires, as we say in the States, see what
happens to the carbon dioxide.”
MICHAEL ATKIN: “Carbon capture and storage, or CCS, takes the emissions from power stations
and other sources, compresses the CO2 into liquid and stores it in deep geological formations, or old
oil and gas fields. But the enormity of the task hit home last year, with 11 major projects hitting the
wall.”
JOSEPH ROMM: “Almost every major project around the world that has been started in the last few
years has either been delayed, stopped or cancelled outright.”
The table below lists some of the power station CCS projects cancelled or ‘on hold’. Those
nominally still ‘alive’ are still receiving big Government subsidies and are for operation at
some future date – will that date ever come?
52
Source: Carbon Capture and Storage Projects @ MIT
Project Name Leader Feedstock Size MW
Capture Process
CO2 Fate
Start-up Location
Sweeny Gasification ConocoPhillips Coal 680 Pre Saline/ EOR
Cancelled Texas
AEP Mountaineer AEP Coal 235 Post Saline Cancelled West
Virginia
Taylorville Tenaska Coal 602 Pre Saline Cancelled Illinois
Antelope Valley Basin Electric Coal 120 Post EOR Cancelled North
Dakota
Porto Tolle ENEL Coal 660 Post Saline On hold Italy
Goldenbergwerk RWE Coal 450 Pre Saline On hold Germany
Janschwalde Vattenfall Coal 250 Oxy Saline Cancelled Germany
The dreadful economics of CCS stems from its absurd physics. Firstly the 20% or so of CO2
in the hot exhaust gas flowing at thousands of cubic metres per minute must be separated
from the other 80% - mostly atmospheric nitrogen. That is very difficult and very costly to
do at all, let alone to do consistently 24/7. Then the CO2 must be compressed and this needs
huge power – typically about 30% of the station’s electrical output. In turn this means that a
putative CCS power station must produce around 50% more power than it can send out to
the electricity grid which means that it must burn up to 50% more coal than a non-CCS
station of similar output. It therefore needs bigger and more costly furnaces, boilers and
generators. That makes the price of electricity soar – even at this stage.
Then the CO2 must be piped to a ‘suitable’ underground storage site which may be far away
and will need extensive and expensive drilling. The final absurdity lies in the relative
volumes concerned. One m3 of coal in the ground weighs around 1.4 tons. When burned that
gives over 4 tons of CO2 which has a volume of over 2,000 m3. So 1 m3 out of the ground and
2,000 m3 back – no wonder the costs go off the clock! Given all this nonsense the question of
whether or not the CO2 will stay underground for centuries is a mere bagatelle.
Some people have been misled by reports of successful ‘CCS’ projects. They all involve
injection of CO2 into oil or gas wells as part of the process of winning oil or gas. ‘Re-
injection’ of separated gas into an oil well to maintain reservoir pressure and enhance oil
recovery is a long-established practice in the industry. When CO2 is available at the well-
head it makes good sense to substitute it for the natural gas (CH4). The CO2 is not saleable
but the natural gas commands a good price so it is piped to customers and the CO2 is
injected instead. All the drilling has been done, the pumps are already there and the
53
compression is needed anyway so the extra cost is negligible. This process has no relevance
to CCS for power stations.
Injection of CO2 in the subsoil for
recovery of oil.
http://www.basinelectric.com/Energy_Resourc
es/Gas/CO2_Sequestration
The Port of Hong Kong and World Shipping
The Port of Hong Kong
is one of the World’s
three great container
ports and handled
some 23,700,000 teu
(twenty foot equivalent
unit) in 2010 – nearly
5% of the entire
World’s container
traffic. What Hong
Kong already does for
the environment and
for maritime safety is to
ensure that all vessels passing through the Port and all bunker fuel supplied by the Port
comply fully with the latest requirements of the International Maritime Organisation (IMO).
The Port should also ensure that all local vessels under its jurisdiction which have diesel
engines fit DPF and SCR units and use only <10 ppm sulfur fuel oil.
In 2010 the Port of Hong Kong supplied some 3.8 million tons of marine diesel and 6.4
million tons of fuel oil as bunkers to visiting ships. As a long term aim the Port might, with
cooperation of the IMO and other great ports, require visiting vessels to burn only low sulfur
fuel within a given distance, say, 24 nautical miles of the Port. The State of California, for
example, imposes such a requirement on all vessels up to 24 miles off its west coast.
54
Air Pollution from 2-Stroke Motors
Two-stroke engines produce a steady stream of unburnt lubricating oil plus other pollutants.
This is inherent in how they work. One small, 2-stroke motor bike can produce more air
pollution than many cars. Thus 2-strokes (below left) are bad news and they need to be
phased out in favour of 4-strokes or all-electric bikes such as that shown below right.
Photo: Robert Hanson June 2012
This boat uses twin 4-stroke motors. This is much better for water and air quality than using
2-stroke outboards.
55
Conclusion
Hong Kong, The Fragrant City, should have clean air to match its clean streets, to benefit the health and well-being of its citizens and to maintain the strength of its economy. This requires emissions from vehicles and all other engines to be controlled very strictly. Lasting credit will accrue to those who make this happen. For all new equipment it means imposing the highest international standards which will be embodied in HK6. For all existing engines it means, over a period of 6 years, upgrading those engines to that same HK6 level and, if upgrading is not practicable, scrapping the engines. HK6 limits based on emissions per KWhr will apply to all diesel engines within HKSAR whatever their use and whatever their location. In particular, HK6 will apply to all vessels using Hong Kong harbour on a regular basis and to all equipment on construction sites. The resultant clean City air will be a fine example from Hong Kong to other Cities in the World. This will need much effort, money and concentration on the essential task of implementing HK6 by 31st December 2018.
So: Clean up Hong Kong’s old and dirty diesels as the highest priority.
This report invites everyone in Hong Kong, whatever their role, to get stuck in vigorously to the hard but entirely achievable job of making their home air clean.
56
Appendix A - The Relationship between Emission of CO2 from a Diesel
Engine and Emission of Criteria Pollutants
There is a widespread belief among many sincere and well-meaning people that emissions of
CO2 and emissions of harmful (criteria) pollutants from diesel or other engines are closely
linked. Taken over time, this belief is the opposite of the facts.
For a given engine using a given fuel it is true that the more miles it travels or the more hours
the engine is used, the amount of CO2 emitted and the amount of the various criteria
pollutants emitted will rise together.
But over time, in particular across the years from 1990 to date, there has been a complete
disconnect between the emission of CO2 and of criteria pollutants. During that period the
total amount of CO2 emitted has risen pro rata with the increase in engine and fuel use but
the total amount of pollutants emitted has fallen drastically. That is to say the two emissions
have moved in exactly opposite directions. Numerous publications, e.g. from USA EPA and
the EEC, show this to be the case. More CO2 and cleaner air have gone hand in hand. A visit
to any major European city makes this very obvious.
How can something so contrary to so much intelligent opinion be true?
The very large improvement in emission controls (and thus in criteria pollutant reduction)
has far exceeded the increase in engine and fuel use over the same period. CO2 emission is
directly proportional to fuel consumed so it has risen. Simultaneously the ever better
emission controls fitted to new engines have reduced criteria pollutants by orders of
magnitude. The reducing effect of those better controls has been much greater than the
increasing effect of rising fuel use and thus CO2 emission. Hence pollution has fallen while
CO2 has risen.
This is such a key issue in the Pollution/CO2 debate that the authors decided to risk boring
readers by spelling it out with detailed facts and figures. In part, it repeats matters already
covered elsewhere in this report.
CO2 from Diesel Fuel. When a given quantity of diesel fuel is burned completely – whether
in a diesel engine or elsewhere – it produces a given amount of CO2.
Fuel type Kg of CO2 per unit of consumption
Grid electricity 43 per kWh
Natural gas 3142 per tonne Diesel fuel 2.68 per litre (3.23 per Kg)
Petrol 2.31 per litre
Coal 2419 per tonne
LPG 1.51 per litre
The table above is from Exeter University in the UK: http://people.exeter.ac.uk/TWDavies/energy_conversion/Calculation%20of%20CO2%20emissions%20from%20fuels.htm
57
This can be confirmed from countless other sources. The amount can vary slightly with
variations in the exact composition of a particular fuel.
Source: http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption (BSFC)
Examples of values of BSFC for shaft engines
The following table takes selected values as an example for the minimum specific fuel
consumption of several types of engine. For specific engines values can and often do differ from the typical values shown below:
year Engine type Application BSFC in lb/(hp·h)
BSFC in g/(kW·h)
Energy efficiency
Turbo-prop
0.8 360 to 490 17 to 23%
Otto cycle gasoline engines
.45 to .37 273 to 227 30 to 36%
Diesel engine turbocharged diesels
.34 to .30 209 to 178 40 to 47%
1945 Wright R-3350 Duplex-Cyclone gasoline turbo-compound
aircraft engine
0.4 243 33.7%
Toyota Prius THS II engine only [2]
Automobile
225 37%
1931 Junkers Jumo 204 turbocharged two-stroke diesel
aircraft engine
210 39.8%
2002 Rolls-Royce Marine Trent marine engine
210 39.8%
1949 Napier Nomad Diesel-compound
aircraft engine
0.345 210 39.8%
58
2000 Volkswagen 3.3 V8 TDI (Diesel)
automobile engine
0.33 205 41.1%
1990 Audi 2.5 litre TDI (Diesel) auto engine
198 42.5%
The above table from Wikipedia shows how minimum specific diesel fuel consumption has
changed very little from the Jumo diesel of 1931 to the Volkswagen diesel of 2000. Both are
very economical engines. Comparison of the Audi engine of 1990 and the Volkswagen
engine of 2000 indicates that bsfc and therefore CO2 output per KWhr may have risen
marginally over that decade.
Average consumption for trucks and similar diesels in everyday use is significantly higher;
around 240-250 grams (0.25 Kg)/KWhr. It has changed hardly at all between 1970 and
today. In turn this means that CO2 output per KWhr of diesel power has not altered
significantly. It has remained around 3.23 x .25 = 0.81 Kg/KWhr over the period 1970 to
2012.
What has happened to emissions of criteria pollutants from diesel engines over the same
period? Criteria pollutants are treated in some detail elsewhere in this report. Those that
come from diesel engines are: SO2, CO, NOx and PM. The first is not a function of the engine
design but of the composition of its fuel. If there is sulfur (S) in the fuel it will burn to
produce SO2.
http://www.dieselnet.com/standards/eu/ld.php
Carbon Monoxide (CO), Hydrocarbons HC or VOC), Nitrogen Oxides (NOx) and
Particulate Matter (PM or RSP).
The tables from the EEC (pages 17-21 above) show the reductions in allowable emissions of
those pollutants from 1992 (EURO I) to 2013 (EURO VI). EURO I itself was a large reduction
from the high pre-EURO figures.
Between 1992 and 2013 there are mandated reductions by various large factors for the four
pollutants as follows: CO 3; HC (VOC) 8.5; NOx 20; PM 61.
Specific diesel fuel consumption remained the same over that time so in each case the
Pollutant/CO2 ratio was reduced by the factor shown.
The relationship between CO2 and the pollutants, SO2, CO, HC, NOx and PM over the years
1992 to 2013 are set out on the table and graph below. It is based on an engine of 80 KWhr
59
with an sfc of 250 grams/KWhr running for 1,000 hours. It may be used in any application,
e.g. a bus, a truck, a tractor, a vessel or a stationary generator. As each new EURO
specification comes into force the previous engine is replaced with one conforming to the
new standards.
The table and the graph show the total fuel used, CO2 produced and pollutants emitted over
the course of a full year. The scale is as shown above the graph. It is based on the EURO
figures as above and with sulfur in the fuel being reduced from 0.2% to 0.001%. Broadly
similar figures would result from using data for other countries, e.g. USA or Hong Kong.
80 KW diesel engine
Table and graph are calculated by the authors from the data on pages 19-20 and show: Diesel engine of 80 KW running for 1,000 hours each year, i.e. producing 80,000 Kwhr/year.
Upgraded to comply with new rules each time there is a relevant change in the EURO standards.
Table shows fuel consumption plus CO2 produced and emissions of criteria pollutants in total for each year.
Table and graph show how CO2 production remains steady over the years while pollutants drop dramatically.
Fuel and CO2 are in tonnes/year. Pollutants are in Kg/year.
Yea
r 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13
Fuel 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
CO2 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6 64.
6
SO2 200 200 80 80 20 20 14 14 14 14 14 14 14 2 2 2 2 0.4 0.4 0.4 0.4 0.4
CO 360 360 360 360 320 320 320 320 168 168 168 168 168 120 120 120 120 120 120 120 120 120
HC 88 88 88 88 88 88 88 88 53 53 53 53 53 37 37 37 37 37 37 37 37 10
NOx 640 640 640 640 640 560 560 560 400 400 400 400 400 280 280 280 160 160 160 160 160 32
PM 49 49 49 49 20 20 12 12 8 8 8 8 8 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 0.8
60
Scale: PM, HC & SO2 = Kg. CO & NOx = Kg x 10. Diesel Fuel & CO2 = Tonnes
The table and the graph show how a few, old and high-polluting engines remaining on the
far left side of the graph can negate all the good done by many modern, low-pollution new
engines on the right hand side.
This again emphasises the critical need to get engines of an old and dirty design
upgraded or removed from use in Hong Kong as soon as possible.
0
10
20
30
40
50
60
70
80
90
100
92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13
SO2
HC (VOC)
CO2
NOx
CO
PM
Diesel Fuel
61
Appendix B – Air Quality Action to Date in Hong Kong – Summary
The authorities in Hong Kong have been very well aware of the Region’s air quality
problems for many years now and (as noted above) a variety of measures have been taken to
improve matters. These have had varying degrees of success.
An unequivocal success has been the action on sulfur. The sulfur dioxide gas (SO2) produced
when sulfur containing fuel is burned is one of the most damaging air pollutants. It forms
thick smog and has a very harmful effect on human lungs and airways. It also damages
buildings and the environment in general with its infamous ‘acid rain’.
Hong Kong has made a two-pronged and highly successful attack on SO2 pollution. The coal
burning power stations have retro-fitted the very best FGD (Flue Gas Desulfurization) units
which remove almost all the SO2 from their exhaust gases. Simultaneously the Government
has required all diesel fuel for road vehicles to have no more than 10 parts per million
(0.001%) of sulfur. These two actions have combined to give Hong Kong a much lower level
of atmospheric SO2 than most comparable cities. Hong Kong is outstanding among its peers
in having a level of SO2 that is only half the strict guidelines set by the World Health
Organisation.
For a solid fuel like coal, sulfur can only be removed after the fuel has been burned. For a
liquid fuel like diesel, which goes through a refinery before sale, it is much more effective to
remove the sulfur before the fuel reaches users. Thus SO2 emissions from vehicles are
controlled by limiting the amount of sulfur permitted in their fuel to near zero.
There is more. The ultra-low sulfur content mandated for road vehicle diesel has laid the
essential groundwork for the optimum functioning of DPF and SCR units as and when they
are fitted to road vehicles. Any significant amount of sulfur in the exhaust gas can ‘poison’
the catalysts in a DPF or SCR unit. No such ‘poisoning’ happens when sulfur in the fuel is
below the 0.001% level. Thus Hong Kong has already taken the crucial first step to allow
diesel engines in road vehicles to effectively use the very best pollution control equipment
and thus achieve clean air.
The one qualification to this is that the .0001% sulfur limit should apply to all diesel fuel
used locally in Hong Kong; that is to diesel used in construction plant, stationary engines
and vessels including ferries. This will enable those engines to use DPF and SCR units and
thus reach the high standard of emission control needed to give Hong Kong clean air. This
will, of course, increase the cost of diesel for those users.
LPG (Liquefied Petroleum Gas) and DOC (Diesel Oxidation Catalyst)
Both of those stratagems are in use in Hong Kong. They ‘seemed like a good idea at the time’
but in today’s world they are but a poor man’s solution to pollution control.
62
LPG: In the early days of pollution reduction in vehicles, LPG did have an advantage over
petrol. By the time EURO III, let alone EURO VI, had been reached that advantage had
disappeared and LPG had become just one alternative hydro-carbon fuel for use in ‘Positive
Ignition’ engines. In modern engines LPG is neither better nor worse than petrol so far as
emissions go. Pollution corresponds to a vehicle’s EURO category irrespective of the fuel it
uses. Selecting or not selecting LPG must rest on other factors such as price.
In passing; the small red diamond attached to all LPG vehicles is not a badge of merit. It is
an internationally-recognised warning, especially to Fire and Rescue authorities, of the
dangers inherent in such a vehicle.
DOC: In the 1990s DOCs, Diesel Oxidation Catalysts were widely used as a quick and fairly
cheap ‘fix’ to reduce PM emissions from diesels somewhat. They were retro-fitted to many
diesel engines in Hong Kong.
In general a modern engine will have far better controls and thus far lower emissions than
an older design. For example, a diesel engine fitted with a good DOC will trap about 30% of
the very harmful PM whereas one with a fairly modern (EURO V) DPF will trap about 90%
of the PM. If the DPF is to the latest (EURO VI/HK6) standard it will trap about 95% of the
PM.
At first glance it might seem that either DPF is about 3 times as good as a DOC but, in terms
of the pollution that is allowed to escape to atmosphere, the 90% one is 7 times better; the
95% one is 14 times better. These are typical figures for real world engines and underline the
great benefit to air quality of using the best modern pollution control system. For a given
amount of use and therefore of fuel consumed each engine will produce the same amount of
non-polluting CO2 - but very different amounts of harmful pollution.
DOCs have no effect on the emission of NOx – nor do DPFs. Good control of NOx requires
the use of an SCR – Selective Reduction Catalyst.
Footnote:
Researchers Find Material for Cleaner-Running Diesel Vehicles
Discovery May Yield a Cheaper, More Efficient Alternative to Platinum in Automotive
Engines
Aug. 16, 2012 Mullite is a silicate mineral discovered on the Isle of Mull, Scotland in 1924.
Laboratory tests indicate that converters using Mullite would have 45 percent lower
emissions than with platinum. University of Texas at Dallas via Phys.org.